Replacing a crank shaft questions

like_A_pike said
My engine is a 1971 340 (august I think). Externally balanced.
I have a manual for 1968 and the only thing it says regarding identification is whether I have a Maltese Cross stamped on the “numbering pad on the right side of the block” . It may have undersized one or more bearing journals by .001. If it is stamped with that cross and an X All of them are .010 undersized.
Is this Maltese Cross Id still true in 1971 or 72? Do I need to worry about it if it’s heading for the machine shop? Where is this numbering pad? Will any LA crank shaft work or is there something specific I need to target?
Thanks in advance

As stated, your '71 340 was a factory forged crank- INTERNALLY balanced (if unmolested factory). Keep it as opposed to the cast 340 crank, unless it's all you can come up with. Like krazykuda said, they use their own external balance damper AND their own balance on the flywheel/TC which is unlike any other smallblock, including LA360s and 5.9 Magnums.
And no, you don't have to worry about your -.001 or -.010 crank if it's heading to the machine shop anyway. Any undersizes are dealt with with appropriately sized bearings.