I should know better than to say 'all' when speaking of Panteras, since DeTomaso did use whatever parts he could get. If your steel firewall and aluminum adapter stand-off is drilled for only three bolts and not a dual 3-and-4 bolt drill pattern, then I shall accept that the Pantera did in fact come from the factory with both bolt pattern boosters. You have a '73, don't you, Forest?
I do know for a fact that there were at least two different boosters used- a slightly larger OD booster was used on Gr-3 street-racers since i installed one on a member's car in '83. It barely cleared his chrome bumper '72's latched front hood and to get that much clearance I had to make sure the assembly was pushed all the way down against the (4) mounting bolts and the latch pin was bent a bit.