Yes, less overtones, but all the nice deep that maple gives. I've has Sigs and the dryness just didn't do it for me. Maple seems to have a nice "sparkle" at the high mids too.
Actually the 12x12 wouldn't need to be re-lugged at all as the lugs on these early drums only came in two or three lengths. A 12x12 tom has the same lugs as a 12x10 tom, but the tension rods are different length to make up for the disparity. See the 14" tom as a great example.
The thing that's gnawing at me, after the cost, is that they are Black--not necessarily bad but very Phill Rudd. Also you said it Greg--Heavy Rock. I'm not playing that style these days so much and probably won't in the future. A 22 is doing me just fine right now and 20's are an old fave of mine.
I like the rarity of the thick shells, but my old Maple Lights sounded incredible. I play Yamaha Beech Customs now and let's face it a good drummer sounds good on any kit. If I do say so myself.