Duh, finally blacklighted my favoritest Chipcos and found those barcode markings Jill! They appear on the Hotel El San Juan Girl & Beachball chips which are credited as the first ever Chipco used in a casino, 1989 (reading JB's post sure is interesting though!). The earliest USA Chipcos I have ('90 - '92 Bally's and Harrah's Sailboat) don't show any UV markings. BTW, and this is a potential monkeywrench , I got these Chipcos from the auction of guess what, "Caro Collection" lots! Another bulletin! One of the seven $1 ESJ Chipcos I have does not have these UV markings at all while a few of the other chips have very faint barcode markings. I wish Caro hadn't had possesion of them so's we could eliminate them as the source of the barcode UVs As I make it out, we can say that Chipcos exist outside of these Harrah's bogies with barcode UV's but can we really say Chipco put them there? Oooof!

The El San Juan chips shown in the scan have been pixilated and manipulated digitally to remove the cancellation holes drilled intheir unfortunate little faces. I only wish I had uncancelled examples and none of my El San Juan chips are for sale or trade at the moment... but never say never, right?