If you have a core, send it to Booster Dewey. There were two different kinds of boosters used. The most common is the Midland Ross booster. It is held together by a band and is zinc-dichromate plated.(yellow/gold plating) The second style is a Bendix. I haven't seen this booster very much in the later years but occasionally it pops up on original cars. The Bendix booster is crimped together and was painted black.
Here is my original Midland Ross booster after coming back from Booster Dewey.
As for the mastery cylinder, you should still be able to get a correct looking reman from a parts store. The brand new masters I've seen aren't correct. The new masters have the squared off end towards the front of the car. Originally, the rounded end was facing forward.
