help with engine stamp #

[smlcuda]

hi all new here.
i have a 340 in my 73 cuda. engine vin on right side bottom matches vin.
front left below head says 3m340 03158067
i assume 3 means year m means mound road plant 340 thats pretty clear. would 0315 be march 15 and 8067 the sequence
thanks steve l