Yeah Bazooka would probably behave like AT grenades (I mean, it does fire an AT grenade) So it'd pretty much be ohk most of the time, and it'd largely be HP based.
I hadn't considered the Boys though, and it was more down to the Type 95's level. Off the top of my head I believe it would penetrate somewhere around 23ish mm on average (dunno what kind of steel that was though)
Though I think it had tungsten ammo that helped but I don't think they ever issued that stuff
INB4 AZZ says something about tungsten Boys ATR for Axis.
small arms fire could penetrate around the engine, I believe, although it'd be like LMGs, and hi-power rifles.