John, I'd need some time.
It's a worthwhile project to make a nice coherent reference with everything in one spot - though not totally easy. Cross-checking back and forth between the Kleeberg COAC chapter, your two updates which both have different formats and some duplication and such that needs to be coalesced... PLUS my own files which (and I have saved pics of a number of pieces not in any of those)... is cumbersome. Also, judging rarity of various types is almost total anecdotal guesswork with the main reference being so old/completely before the
ebay era. I've thought for a while that a website with current knowledge/updates - along the lines of what the CC Bust Half Davignon ppl do, "Bad Metal", etc. - would be a great thing.
Meanwhile, a couple thoughts in general and on the piece threefifty posted.
--- Obviously the sole focus of the original Kleeberg project was the 2 Reales. This denomination (as genuine) was a frequently used workhorse coin here, probably more so than the other real denominations. As such, it clearly got more of the counterfeiters' attention in terms of output, so it's the most pertinent.
That said, I STRONGLY think you should expand the project to include what would be the first actual treatment of the other minor denoms., 1/2R, 1R and 4R. I'd say maybe 1/4R too, and I've seen a number of those, but they really saw little to no use here in the Colonies/States - do you want a "pieces that circulated here" focus, or to open it up to pieces suspected/known to have emanated from elsewhere like you and Bob's 8R treatment does? Obviously that's a bit of a different beast given the 8R's global circulation/appeal as specie/trade coinage, but worth weighing as a general question.
Those other denom. CCs are all SO desirable due to their scarcity overall, particularly to the advanced collector who recognizes this from experience... Obviously, would be a bit challenging to ascertain which pieces have actual USA links, saw usage here... but that's the case for the 2R also, no?
E.G., I have a pic (not sure if I bought it or not?) of a rather frequently seen Mexico 1804 CC 1R (have pics of at least 8 examples)... and one has the known "F. A. VACHE" merchant counterstamp. So, fairly solid proof that it's a counterfeit which circulated here - plus, if only from memory/impression, seems they almost always surface out of the USA. On the other hand, you have something like the common Santiago 1808 4R... "imitation". I recall Carlos Jara stating somewhere that these dated ca. 1870... and just from observation, they almost always come out of South America or Spain.
--- threefifty, if you've posted this one b4, I'm blanking on seeing it previously. If so, shame on me, really interesting piece. The JP assayer reverse is obviously impossibly late for that obverse, thus it's effectively a muling of mismatched obv and rev.
First things first... I'm going to say that the last digit almost certainly must be 8. This piece is rather accurate detail-wise, though obviously to (2) different coins (the obverse looks "mostly" faithful to an original regal piece - see below)... If you take a run through 1783 2R from Lima or any other mint, they used a defined flat-top 3. Compare 1788 issues in auction archives...
--- This coin, and the piece in John's 2017 update that he referred it possibly matching, both sort of raise a larger issue in several ways. That issue, which can be tricky... is how to handle/classify pieces that clearly seem to more accurately be considered simple casts rather than "hand-engraved" types. John, I believe I've mentioned to you before... I believe a number of pieces in your 2017 work are basically just simple, faithful-to-the-original casts of regal coins. (I would suggest doing a good cram review of genuine coins from all mints/dates as a refresher for this project). These, of course, aren't as sexy to collectors in this area, BUT YET are absolutely an intricate part of the same conversation... they were literally made for the exact same purpose!
However, what's the cutoff for being defined as the criterion for making it a true "Kleeberg" type? Traditionally, it's hand-worked dies...
So, along those lines... John's "K.83C - L51" is one of the pieces that for me is simply a perfect copy of a regal piece. I would not include that as a Kleeberg. Perhaps, though, a factor is how we think it was manufactured...
Then there's this piece threefifty posted... Firstly, John, this obverse is absolutely is NOT any precise match to your "K.83C" obverse. Referring to that last digit, whether an 8 or now, CLEARLY the tops are vastly different; there are other obvious visible differences as well. Careful comparison of design elements, legend character positioning, etc. is REALLY important here, obviously.
That said... OK, we know at least SOME deviation from simply casting a regal example (1788 or 178-whatever) occurred since we have an impossible muling of date/assayer. Looking at this piece... I'm a bit torn since most detail (e.g., the portrait) looks quite accurate/regal, to where I'd suspect a simple obv and rev cast (but again, two different muled)... however parts of the legend lettering, perhaps the pillars on the reverse, and also the denticles sort of look a tad "touched up" by hand.
Just on the fact that it's an obv/rev muling alone, I would definitely say it's a distinct-enough piece to merit inclusion.