454 harmonic balancer 8 inch date decoding? Stumped
 

Guys i got an 8 inch 454 harmonic balancer with the numbers cast inside of the back of the balancer. Numbers read 1 38-3X. I cant find any other cast date numbers on this balancer. Being an 8 inch balancer tells me its a High Perf BB balancer correct? What does these cast numbers mean 1 38-3X? Also the balancer has the original orange paint on it. Any help is greatly appreciated.

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