Before too many people get bent too far around the axle, I'll tell you a couple of things.
Any modification that would have required changing a stock CNC program, such as a custom inlay or a different sized PUP, was, and continues to be, an absolute no go for anything less than a Private Stock. Just one change like that would make any run a run of PS guitars, with pricing to match.
So the problem became how to make the guitar permanently identified as a "Forum Guitar" without having to consult paperwork, MODCAT designation, secret symbol under the bridge or what have you. It needed to be something integral to the guitar, not removable.
Etched pup covers? No.
Forum TRC? No.
Writing on cavity covers? No. (PRS agreed to this one)*
All of those things could be removed and placed on another guitar and/or easily duplicated by anyone with even a little skill.
What the dealer and I asked for was writing on the back of the headstock UNDER the finish. Something like "Forum Guitar 2018" would have done nicely. The dealer has excellent relations with PRS and fully understood the things that killed the last attempt at a Forum Guitar.
The answer from PRS was, "No."
I'm not going to defend or criticize PRS's decision. It is what it is.
Time to move on.
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*PRS agreed to writing on the removable cavity covers. If anyone thinks this is a great solution and wants to move forward, contact the dealer of your choice and start it over. It makes no sense to me, however, to have something removable or easily copied as the designation. YMMV.