I *think* this is an inexpensive import. Google "German .22 revolvers" or something to that effect.
If it is what I think it is ("Buffalo Scout" - I believe also an FIE gun, see below), quality will be hit/miss. Suggest you take it out and shoot it before spending $ on spare cylinder.
Case in point: I had an FIE .22 in college that would, on a good day, hold minute-of-barn at 20 yards.
Yours might different, but I'm not going to hold my breath for you.