With no other vacuum options, the location under the passenger's hinge seems to be consistant at least to other findings. Somebody else (would need to go back in this thread) indicated a similar type and design for a non-AC tilt wheel car.
Might be that one in my post - same location - different IMHO vacuum canister. Just doesn't look like the tomato can version to me - like the one we see in the EBay ad
Just to add a link to another related discussion
https://www.concoursmustang.com/forum/index.php?topic=9499.msg56963#msg56963
