1998 LMC Zinclon? Silver Penny

There are multiple non-destructive surface analysis techniques like Energy Dispersive Spectroscopy (EDS), but I'm not sure that this coin is worth going to that level of effort since I think it would only be worth face value. I think that @merc steered you correctly.

check the edge for signs of copper, and if you see none, then I'd say scrape the EDGE in a small location with the point of a razor blade or exacto knife and see if you can uncover copper.

I will be honest here, legit unplated zinc cents are relatively shiny and have mint luster if the planchet missed being plated and was struck by the dies. it depends on how long it's circulated. the shininess isn't the determining factor. there's graded mint state examples that pop up from time to time that look like this.

if it was deplated, they go to a flat grey black. It's possible this is a unplated planchet.

I suggest looking it over for signs of copper with good, clear magnification, and if you don't find any, scratch a little bit on the edge of the coin, very small and take a look, don't go too deep because if it was plated over the copper, you will get down to the zinc core and it won't help to make the determination.

Look, I know people are going to say "don't damage the coin". the fact is the "no damage" methods are expensive and if it's plated, it's not worth the cost to do it, or the cost to send it for a grading company to look at either. I don't suggest spending money for material composition analysis.

do it as small as possible in the least conspicuous place, and you'll know the answer. try to scrap off some surface plating.

If you see any copper on the coin, it's been plated.

it wouldn't be "silver" or dime stock. If anything it would be an unplated zinc planchet, it would of missed the plating step.

A copper plated zinc cent weigh only 2.5 grams (+/- 0.100 g.) the copper plating on a zinc cent is approx. 0.0521 g so even if it was missing weight wouldn't be a determining factor because it would still fall into the 0.1g. mint tolerance/variance. weight can be checked of course, just it's not going to be totally conclusive.

if it was copper plated and replated, it could still fall within mint tolerance/variance. obverse looks spotty, but this could be the zinc beginning to oxidize. I see no evidence of "Split plate doubling" which if it were replated, it would still be there from original minting, if it existed in the first place on the coin.

Now, I agree, most likely plated, HOWEVER, I can't prove that conclusively from these pictures, I don't find fault with it and it's consistent with AU-Mint state Unplated zinc cents I've seen that were authenticated. details are sharp, if it was plated, it would of been plated twice once by the mint with copper, then a 2nd time. I can't see the steps on the reverse NOT being mushy with an additional plating happening to it. the strike SHOULD impart luster to the coin, it shouldn't be exaggerated, but it should be present.

the scale pictured rounds to 0.1g also, so it's not sensitive enough to weight for the .05 gram variance if it exists. The scale will only do 2.4, 2.5, 2.6 ect. it could be 2.45 to 2.55, the scale can't tell you though.

I did some calling around a found a high end pawn shop with xray machine, will let them look at some of my gold coins and have them xray my silver penny.