Plymouth Factory Service Manuals... something odd.

Is it possible it's simply a difference in paper? Don't know. More importantly, there ARE errors. I don't remember all, but a couple:

Some years, the rocker shaft bolts which are 5/16 bolts, are improperly listed at 3/8 torque values. You can twist them off

Also, a few years right in that area, a couple of wires are crossed up in the bulkhead connector listing. You can easily figure it out. I believe it involves the green/ red horn wire, and the yellow start wire