Nope, no P as an assembly plant code.

Do not trust everything you see on the YO site.

On the 72 block the oil pan pas IS 2B453085, and HM340R39538019 on the front

on the 69 block Bh29p9p162347 ( the second "p" could be an "r" oil pan rail Ew340P262200125

I had my wife look at them and this is what we came up with. Some of the numbers are double and triple stamped along with some random 2's upside down. We tried to take pics but they are too fuzzy to see anything. We also tried to do some rubbings but not all the letters would show up

Double and triple stamped would make me think they are restamped blocks not factory markings.

Not always Stumpy, I see factory double stamped, etc. blocks all the time

Exhibit "A"

It almost looks like the stamp Bounced as thay struck it or something like that

The machine often bounced from the recoil, so ghost images / stamps are common.