Some of those lower units have the plug held in place by a 1/4-20 NC screw that threads into the backside of the cone from the inside of the lower unit.

As such, I’m not sure that the plug in the front of that foot is a simple press fit or not.

I’m not sure if the heavy foot with the wings on it is built that way, but you may want to look into that. I’m more familiar with the early 1930’s Speeditwin lower unit than anything else. Hope I don’t cause any confoosion.

Best,
PM T2