okay, so here's the scoop. I got the replacement mount from them today. and its the same as the 'wrong' one they sent me before. however, this one is labeled.
the 'wrong' ones they sent (on the right in the picture above) are part # 25994881, whereas the one on the left in the pic is 25791031
from what I can find, the 25994881 is the superceeded part number for 25791031 from GM. after reading some of this monster post:
I see that people who are swapping these in are using both part numbers. I've seen a couple who mentioned that using 25791031 had a 'clink' noise every once in a while, which might be why GM changed to 25994881 which has a much smaller center hole as you can see in the pictures. either way, it looks like either upper mount will work, so since I already have 2 #25994881 I'll be using those along with the 25791032 lower cushions and 15854745 washers.
that thread above is monsterous, but when I do mine, I'll take pics and do a write up on it as well.
Jeff, do you still want me to get dimentions of these so you can check if they'll work on yours? let me know and I can get out the calipers