E23-2 Bridle Lifting Question and Bilge Curiosity

I have a new to me 1976 E23-2 fixed keel model. There's a round access hatch in the center of the cabin sole at about the center of gravity. In the bilge it looks like iron and has threads that go down about 3". Does anyone know what this is? Could it be for a lifting eye to be threaded into? I attached a pic.

Any Ericson 23-2 owners left here? Has anyone designed a bridle lift for one?

Thanks!