1987 Caomanche pickup flywheel access panel

Anyone know if the two huge bolts at 3 o'clock and 9 o'clock that connect the engine block to tranny need to be loosened or removed to drop out the flywheel access panel?

Haynes and Chilton and Petersons - none of them explains removal at all and it's not a no-brainer.

I'm putting in my THIRD oil pan gasket - just cannot get a seal at the rear because of that blasted flywheel panel. Every time I slip the pan and gasket into the space available I think the gasket is being shoved forward and allowing seepage. Removing the pan would allow straight up install of the pan till it cures and THEN replace the flywheel panel.

Thing is, I'm not comfortable removing those two bolts without being sure of the consequences.

Any ideas...anyone?