Well, I don't know about HST, but you know who might be able to shed some light on this issue: John Martin and Linda Lee Bukowski--you know, ask them if they every heard of, or have in their vast and basically complete collections, or even just saw Buk sign bookplates for random bookplate collectors via requests in the mail (which sounds like something he definitely would've done, as he loved encouraging future contact from random fans and strangers). I mean, there are quite a few people on this forum, and I'd say some even know these folks...so there's that.
Also, doesn't a fake Buk signature on ANY ONE one of Ira's bookplates implicate him not (only) for the signature, but for the bookplate itself--which he has already said are his? I mean--a fake on his bookplate means his bookplates are intermingled with fakes...and are equally suspect, regardless of signature. Like having either the bullets that match a slug/casing (& production lot#) taken from a body -OR- just having the gun which makes the rifling marks--both are compelling evidence of the crime. I mean, is there some nefarious horde of shytsers out there with the SAME bookplates? Are they a some kind of club--like say the Shriner's or the Masons, and they get their shyster-gear wholesale?
Or is it just one dude...a greedy one...with access to eBay and bill's to pay?
It's a mystery...a real mystery indeed.