Did all 1970 E bodies with disc brakes and 10" or 11" inch rear drums come with the 2229171 master cylinder, or was it just used on the cars with disc up front and 11" drum rear brakes?

I think I figured it out……on my 70 E body the master cylinder has a 3461187 casting number which I wasn't familiar with.
After googling that number that is for a 71 and up…. so the master cyl must have been replaced at one time before I purchased the car back in the 80's.

All disc brake E bodies except hemi came with the 2229171 casting number master cylinder. All disc brake hemi cars in 70 and 71 including E bodies had one with casting number 2229191.