anyone balanced a stock 360 crank?

I had my machine shop balance my 360 rotating assembly, I just gave them the stock cast crank, one of those offset-weighted B&M flexplates, pistons (plus rings and bearings), rods, and a weighted Summit SFI damper. Like dgc333 said if you're using lightweight aftermarket pistons and/or rods the factory crank will be way off and rebalancing is pretty necessary. My machinist said it wasn't totally needed for less than 4500 RPM but I'd rather keep things as efficient and smooth as possible and I plan to rev to at least 5000.