I have a feeling that the serial number on your particular block was transferred there from another engine.
I think that's possible, but don't know how probable it is. Everything seems to check out on the VIN with what is on the cowl plate, located on the passenger side, the VIN of my truck is 14DPF2135. It's hard to read the 14 in the beginning but is there. I haven't tried to remove any paint yet, there's Rustoleum slathered over the entire truck, both green and black. I kinda like the patina and plan to leave it as-is on the outside.