And a small correction, it isn't bleach that disolves the real chips, it would be a solvent. Maybe daubing the edge with MEK or plastic solvent, would be enough of a test, without distruction. (destroying something to prove it's real, is counter productive) It would be tacky and dry again.

Maybe we can get the person doing the repairs to add a little UV die, which would not affect the normal look, but a repaired, reconstructed, Etc. chip would glow, like nothing that ever came from the factory. Easy mark, and no deception.

Has anyone investigated the specific gravity or just weight possibilities for identifying real plastic vs modern composition?

Speaking of deception, these are some "cheatin dice" that I found in Ohio. Lower right is loaded, the others will take a little study, but the deception is obvious.

Top row, all sides have same three spots repeated, bottom row, look and get a laugh.