Would someone working at an old brewery be muscly?

If they had a job where they had to carry those wooden barrrels, two at a time, one on each choulder, then YES, they would have a LOT os muscle.

Depends on their job. A lot of them would have to be lifting heavy stuff like sacks of grain or big wooden barrels all the time; but there would also be people with desk jobs, like a bookkeeper, who would not need great physical strength (though they might have it anyway).

Depends on what he did.

A brewer might not need muscles, but some guy rolling barrels all day would.

I want it to be realistic too. Like if working here would add to his muscles I want to reflect that, you know? Sounds like an awesome librarian!

I knew a librarian who competed in Mr. Universe contests. You want him muscle bound, make it so...