When I took the engine apart as I was told "It's been Overhauled"... It actually was. New pistons, rod & main bearings...No obvious balancing marks on the crank...
Any other weights added to the crank counter weights? I'm assuming you looked for those already, but some shops don't put the slug into the edge, some will actually machine into the side, so that might be hard to see and/or notice otherwise.
I ask b/c you could certainly neutrally balance a build in order to avoid having to run the offset stuff. I did that with my previous 360 motor and most recently with the 408 W2 stroker, although that really did require a "ground up" balance job b/c of the stroker.
