yes same size. at least mine where.
had a coffman sizzlerpipe with those 3 bolts inhex and stainless
used those when i installed my factory b-pipe
unless my sizzler manifold was rethreaded. but i do not think so.
the only difference i could se on my coffman bolts was that they are a little shorter than the b-pipe bolts. so you can make sure that they tighten up correctly and dont bottom out.