how to identify - heavy duty crank/rods

just a question.... how could i identify a heavy duty crank (318 from 1969 030 over - what tell´s me someone had touched this engine before my purchase) beside a normal one...

the reason why i´m asking - i noticed that i got pressed pins (and if i follow the "how to... book" this should indicate a heavy duty rod (casting 3418645)

on the crank i couldn´t found a 7digit number) where have i to look for it ??

i also asume that this is not the original crank, as in 1969 the pins should be floating ones, or ?

thanks a lot for your help, every input is welcome