Which master cylinder has the screw-on caps?

I picked up an aluminum M/C with two screw-on caps today at my local salvage yard. It came out of a New Yorker and has these numbers on the bottom: 09104 4485297

Anyone know if it is one that will work, assuming I get one of the 2-bolt to 4-bolt adapters? It seems as though the two chambers are approximately the same size. Which one is for the front brakes? It was dark, and I didn't have a flashlight to see where the brake lines ran.

Jerry