crankshaft question?

there was a memo published by Chrysler stating as on April xx, 1972, 340 engines would have cast crank..and it outlined the new damper and converter requirements...

Note: In ’72, the cast crankshaft replaced the forged crank in production on April 11,1972 with 340 engine #HM340R-3911-8000. Damper stamped ‘Use with 340 cast crank only’

Maybe Larry did not get that memo....