Is this factory master cylinder?

[Toro]

In changing my master cylinder on my 72 4wd Blazer, I'm not sure if what I removed was factory or not. After reading other posts across the board, it seems that shallow bore MCs are for power brakes, and the deeper bore MCs were for manual brakes. Mine has factory power brakes, but when I removed the MC, it has the deep bore, and the longer push rod coming out of the booster. Originally this was posted on the truck board regarding bleeding, but a few pointed out that my setup was not correct as it should have been from the factory. And the PO must have changed the MC. I guess it doesn't matter, but it made me wonder. So, do any of you know what the factory MC setup would have been, or did any of you run across this on your Blazers/Jimmys?

Please see the photos below of what I pulled off. Judging from the way it was and looked, if it wasn't from the factory, it had been on there a long, long time.