Neither of you are doing yourselves any favors with the back and forth name calling.
Sheldon - even if everything you allege is true, it's not going anywhere. Postal Inspectors don't care about small, petty-ante fraud. The man-hours it would take to subpoena various service providers and companies like
ebay make the case prohibitively expensive to proceed with.
It's very likely most of your "evidence" is inadmissible. If your tone is ANYTHING like your tone here, it will likely be tossed as entrapment anyway.
Further, there's a big obstacle which is "sales puffery" - a salesman can say pretty much anything s/he wants as long as it's not out-and-out fraud.
In order to settle the issue might require a full forensic analysis, likely destructive.
/1/ The holder clearly looks like the Capital Plastics type including the signature screws which are yellowed with (apparent) age. Does anyone have a contemporaneous CP catalog to see if they made those slabs (if it were a special order as the newpaper ad indicates, might not be conclusive)
/2/ What is the chemical composition of the adhesive on the seals? Is it one that was in use at the apparent time or introduced more recently.
/3/ Same question with the stamp and the ink used with the stamp. Fonts on the stamp also might provide a good indication.
/4/ The entire certificate needs examination. Was it all printed at once? Or is it laser printed onto an offset printed form? The letters are nearly perfectly aligned and that typically precludes a typewriter. It's not impossible that in 1987 a laser printer was used, but it would have been unusual and very expensive. The fonts need to be checked - it's easy to mistakenly use a font introduced long after the time in question.
There are many other things to check, but all of this requires a very high-resolution image of the certificate (front and back) should anyone have one to post.
Still, it's been fun

-----Burton
50+ year / Life / Emeritus
ANA member (joined 12/1/1973)
Life member: Numismatics International, CONECA
Member: TNA, FtWCC, NETCC, EveryCountry (online) coin club
Owned by three cats and a wife of 40+ years (joined 1983)
Author: 3rd Edition of the Sample Slabs book,
https://www.sampleslabs.info/