Engine info below.
I want to remove the oil pan and inspect the sump, oil pump and crankshaft area. I'm not finding any details on this in Bentley's.
It looks like there should be a couple more bolts near the transmission (green arrow) behind the plate (red arrow) which is held on to the tranny housing by the two bolts.
Is this correct???
There are indeed supposed to be 2 bolts back there. If you look at a 1 piece gasket you should see where they would be located, search for pictures on an auto parts website if you don't have one, it looks like that mangled piece of sheet metal is covering them. I've never had to remove that plate to get them but they are HARD to get to, I always have had to use a long flexible swivel extension and a lot of patience. If you put studs there instead of bolts you will have an easier time getting it back on.
If you look at a 1 piece gasket you should see where they would be located, search for pictures on an auto parts website if you don't have one, it looks like that mangled piece of sheet metal is covering them.
That is actually a floppy rubber gasket?

? I'm the original owner for 23 years and don't ever recall anyone removing the pan for any reason. I'll remove the plate and take a look.
CLUTCH COVER WITH GASKET
The seal was a little swollen, but it clung to the plate just good enough to place it in position. Not leak proof, but ok to keep dirt out. Not much oil there so I think I can assume that the rear seal is ok.

2 DIFFICULT BOLTS (poor photos due to tight quarters)
Not quite able to approach straight on due to tranny housing in the way......but not too difficult.....theoretically !! Removing the plate, a simple procedure, makes them a lot more accessible to a wobbly extension and socket.

CLUTCH VIEW WITH COVER OFF
I think that's a rotating part in there....should be the clutch assembly or some such.
Looks like you got it figured out. All these years you never had to fart with this car? Too bad I moved out of Portland a year and a half ago, I could have been driving across the river on weekends to lend a hand. I had to do that anyway to buy my Veg oil.
Now picture up that crank, pump and bottom end for us.
I replaced all the oil pan bolts with socket head cap screws (with integrated washers). One big benefit is making those 2 bolts MUCH easier to get in and out.
A ball-end Allen wrench (3/8" square drive) lets you work all kinds of angles not possible with conventional bolts & sockets.
Steve.