some random thoughts
I think they should match as I believe they are machined as a pair, as well as the cylinder base the chamfers would be mated.
However I reckon if you removed the alignment pins/tubes you could mate them with a bit of very fine grinding paste - usual meticulous cleaning required after
might be as they are only days apart date wise that they were done on the same machine, maybe not how many machines would BSA have had ?.
lot of work putting it all together to find it leaks, maybe bolt it up and shine a torch in it in a dark room.
alignment for the crank - probably line boring would cure any mismatch
Think I'll shut up now before the engineers amongst you have coronaries