Yes that tom mounting system works better than either of the possible 70's mounts and just as well as the 80's Techware so I'd leave it alone rather than "Swiss Cheesing" the top of the drum with more holes. A Techware mount still won't be "correct" nor will it really function any better. Of course they'd be your drums to do as you please if you got them. Looks like a nice set.
Gretsch still uses the same base plate for their current USA Custom and Renown drums (and on some, but not all, of the cheaper series ) so if you can track one down at a store you could make some measurements to see but as I recall that Premier setup is larger than the Gretsch. The cool thing about the Premier is the football shaped down tube can't rotate the way round ones (including Gretsch) sometimes do.
The color of those drums is "Walnut" which is a dark brown. Gretsch's Rosewood is actually a red stain.
