IIRC, it should be right there on one of the throws; I don't have one handy to check. When you say the crank has casting marks, are they a very, very thin ridge at the parting line? (Like shown in the 4th photo in this link?
Cast vs forged crankshaft)
And you can see the rod casting numbers; they will be on one of the wide sides of the rod beam. (Sorry, I thought you still had the pan off....)
Are the TC and flexplate easy to see?