360 oil pan gaskets….One piece, 4 piece??

Yes, the pans are different at the end seal. the Magnum pans do not have those "steps" that 67Dart273 is referring to.
To use the one-piece gasket, you need to pump those "steps" full of RTV (gray or black) and then install the gasket. Or just use the LA 360 gasket set. Not a biggie either way.