Confusing brake issue - need help

[doodah man]

My wife had the truck out so I got her to test it. She pulled the check valve from the booster and didn't hear anything. I guess that means the booster isn't holding vacuum and at least needs to be replaced.

I noticed that lots of parts houses sell the booster and master cylinder together. Is there a reason to change the MC now? I'm thinking that will require bleeding the brakes and since I have to do all my maintenance under an overpass in the city, i try to keep the jobs as simple as possible. But, if the MC should go with the booster I can do that too.