Hi PB; not completely sure but based on the knob count, # of jacks, location of the of/off switch, and fuse post, I think it is (or was) a '56-'59 GA30. Per W. Marx' book; three control knobs and 3 inst. inputs and 1 mic ... I think that's the one furthest to the right. If it's a GA30, it was originally fitted with 8" and 12" speakers and getting a 2nd 12" in there in the place of the 8" would mean replacing the baffle but the none of the grillcloth, tolex, or handle are original anyway. Pic indicates three preamp tubes; if it's a GA30, they'd be 1 6CS7 and 2 6SJ7s. Power from a 5Y3 rectifier and twin 6V6s out. It isn't 60 watts, it uses 60 watts; output 12-15 watts.
Later GA30 (omitted from W. Marx' book :roll: )
Link to a GA30 thread on the Weber BB With the chrome control panel, the CL amp looks like the later version of the amp as pictured above; that's an earlier version in the Weber thread. It isn't clear what the Craigslister wants ... an offer or somebody to tell him what it's worth ... or both. Would be a cool project though.
) identify this amp?