trying to source hubs for sigma brake conversion, anyone confirm or deny?

im pretty sure they are the same. I have a pair of both and didnt notice any difference. If no one else here can give a definate then i could check. But yea im pretty sure they are

Hubs are the same. I have 76 120y it has the same as on front of my 73 coupe.

It depends on what 120y your looking at, sedans came out with different size stub axles. I've compared '74 sedan with another sedan that had the same jap disks (not aussie pbr brakes) and they had different size axels and the hubs were cast slightly different aswell.

Beware as 120y's arn't all the same.
Measure and check things because i've seen standard cars with parts that, according to all available information, shouldn't have come out with them.

Wish i could give you a definate answer.

so the later model hubs would be different, but it would be same to assume that cars up to 76???(think thats when they changed) have the same hubs as 1200 coupe

Lordy, I don't know how often this must be repated.

Australian manufactured sedans from July 1976 used the Armstrong strut assembly & the PBR brakes.

Key words
Australian built/manufactured/assembled
Sedans [& only sedans.]
from July 1976.

All other body types were imported for the full 120Y model run.
Like the other models, ALL sedans up to June 1976 used the Jap spec mechanicals.
I can't be sure but it's possible that some sedans were still imported during the Aussie assembly period, ie, there is no guarantee that a July 1976 or later sedan is automatically an Aussie built one.