7 1/4 rear brake question

You gave me the answer I was hoping for that all 7 1/4 bearings are the same, right? What's this about the late bunch with funny looking covers?
And of course the housing is off to the powder coating shop!
this a strange car being a '76 Swinger which people have argued didn't exist, it's a /6 with 3sp OD, with drums and 4" bolt pattern, ect....
The axles in question that went to the machine shop are out of the original 7 1/4 3.23 rear which had 10" backing plates but the machinist there says the bearings are for 9" brakes and had a different part number for 10". Both rears are 7 1/4.