No. Books should be hammered in the grade for improper pressing that is obvious. Other than that, there is no way to know with absolute consistency if a book has been pressed or not. And attempting to do that would cause CGC to lose all credibility.
I can set 10 books in front of the best graders CGC has, some pressed and some unpressed, (and I would be honest, and set out books that I have owned since they were printed in, say, 1991), and CGC would not be able to tell which books were pressed and which weren't.
I submit books that are pressed to CGC, and I submit books that aren't pressed. Pressing is not detectable with any...and I mean ANY...degree of consistency. You're essentially asking CGC to look for what isn't there. And, since natural processes can often mimic "artificial" pressing (See: Edgar Church collection), there's simply no way to reliably tell.
You're asking for something that simply isn't possible.
How about CGC just rejecting books that it suspects are pressed? How's that for starters? Kind of like "overhang", or perhaps "micro-trimming" - they just send them back to the submitter. (Never happen - not a good business model).
Because 1. CGC doesn't consider pressing to be a problem; 2. Good pressing is virtually indetectable; 3. A ton of books that had never seen a press ever could be "rejected."
It's unworkable. Trimming, even micro-trimming, takes material from the book. Overhang creates problems in the slab. Pressing only flattens out what is already there. Nothing is added to or taken away from the book (despite the "philosophical" objections that "bends" and the like were "taken away." "Bends" are not part of the basic material of any comic, except the spine.)
I think this pretty much sums it up, thanks RMA.