Loss of oil after changing the filter

Hello there!

I am driving a 73 Plymouth Duster. A few days ago my mate changed the oil filter while I was doing some other stuff.

He also released the "baseplate" to change the seal behind. After cleaning the whole thing he fixed a new seal and torqued the baseplate. Then he put some oil on the gasket of the oil filter and fixed the filter.

After starting the engine we have noticed, that the oil is coming out (between the filter and the baseplate). It is NOT coming out between the baseplate and the engine.

My guess: He torqued the screw nut of the baseplate a bit too hard so the baseplate is not "plain" anymore. The gasket of the oil filter can't seal anymore.

It's only leaking when the engine is cold. It stopps when its warm.

Is that possible? If yes - do you have an idea where I can get a new baseplate? Or is there a speacial name for that baseplate?

Thanks for your help and I am sorry about my English!

Greetz from Bavaria,
Danny