[Brian]

I dunno; I built a stroker with a genuine Merc crankshaft that was definitely made of steel. Apparent when drilling the counterweights during the balancing process; iron does not have swarf that comes off in long continuous strips.
I always use steel forged cams in all my builds. They are readily apparent to the eye as they are fully machined, however, I have noticed that if you suspend one and tap it with a metallic object, it'll ring, clear as a bell. The later cast cams won't; just a dull 'thud'.
Pretty hard to 'suspend' any flathead crank whilst giving it a 'ring' test, but I'm pretty sure the acoustics will differ from a cast crank.