Well, if you happen to be looking, I'd be interested to know, but please don't go to any trouble.
I didn't dig too deep, but it looks as if most of the GDW stuff is perfect bound and all of the DGP stuff is staple bound.
yes, that's what my shelves suggest too.
Which is why I was surprised at the stapled Player's Manual. Just to add to the fun, I've heard from someone who has three copies of the PM and one is 'first printing' and also perfect bound, so clearly not a difference between, say, first and third printing.