Master Cylinder Question

PICTURES ADDED:
I am finding that I may not have the correct Master Cylinder in my 72 Grande Coupe. I was looking to buy a new MC cover and seal but my MC and cover is different from what is being sold for a 72 with power front disc brakes. I will try to post pictures later but here is the description:

My MC: rounded small chamber at the front, Rectangular larger chamber closer to the firewall.

What I found to be available for 70-72 with power disc: small chamber in front is square,and the large chamber close to firewall is rounded on the rear side.

So were there diffierent MCs available during these years? or Do I have an MC that someone installed after the fact (not factory)?

Thanks

My Master Cylinder Cap:
View attachment 464994

Replacement I bought:
View attachment 464996

View attachment 464997

Bump for added pictures

ANybody any ideas?

I just looked up the Bendix 11680 and it seems to be the same configuration as the replacement MC cap, Small square resivior and large resivior ronded on one end. Opposite of what the MC is that is installed in my car.

I was checking Napa online and remanufacture MCs are only like $40 so I may just replace the MC and be done with it. Any thoughts?