Master cylinder for Front disc brakes on 67 Barracuda

From my research, no one is rebuilding the 1" disk /drum. You can get the 1 1/32" or the 15/16 but not 1". In disc / drum.

And it will not have the holes for the stock dust cover piston retainer as it uses a snap ring to keep the piston in place.

I have been looking at nos rebuild kits but 40 year old rubber is worry some to me.

I've been looking at drum drum kits to see if the seals are the same but have not removed my OEM master yet.