Normally but not always. Cathode bypass cap in the can for the power tubes is pretty normal, it'll be maybe 25 or 50 uf at maybe 50 volts section. See that on old Ampegs pretty often. Apparently back in the day there was a huge selection of cans or it was easy to order custom ones. Today there's only so much to chose from and once in awhile it's a real pain when there isn't room for individual caps.