Yes, I think they actually are! I have just been living in old MIrage land for too long and thought all bulkheads were the same as those. The Mirage bulkhead has the o-ring seat adjacent to the air transfer bore. I guess they moved it forward decades ago for good reason.What I found strange when I first saw the Mares bulkhead is how the o-ring groove is at the front of the main body of the bulkhead.
Are not the partitioning bulkhead body "O" ring always positioned at the front of the bulkheads rather than at the rear?
Sorry about the confusion!