Bottom end info?

Pulled the crank on the 340 tonight.....it does NOT appear to be a "forged" crank due to all the casting flash on the forward counterweights, but rather a cast crank.....in which case there would be no advantage to using it. Does anyone know exactly when they made the transition from forged crank to cast? This engine (the "doner" engine) is out of a '72 Duster, but was equipped w/ Carter AVS, Hi Flo exhaust manifolds, and has the "X" heads w/ 2.02 intake valves and has a casting date (?) of 10-69 on the right side of the block. The pistons have the valve "smilies" on them.The damper is thinner in diameter than the one on my "good" 340 and does NOT say "Use with cast crank only" as the one on my "good" 340 does. Anybody know the answer here?
As always, thanks for your help. I knew all this once, but have "forgotten" over the course of time! You guys are awesome!