I have it on my 400. What's your question?
If I was adding a Samson post I would add far more than a piece of glassed-over marine plywood. I added a windlass to a 43' boat. Had an engineer approve my plan, which included tying a backing plate to adjacent bulkhead, with four or five layers of (I believe)1708 fibreglass and West System epoxy. Don't underestimate the loads that will certainly be imposed at some point.I am not at the boat but I have photos from my survey in 2018. This shot, I believe, shows a glassed-in piece of wood with the through bolts showing in the anchor locker pointing forward.
I don't know what is underneath, that would be hard to find without disassembling something.