I don't have a leak down testing rig or the air to put into it so I did another compression test on this cylinder and tried some advice I'd learned from CE.
I tested it dry and it came up to about 140 psi after about 10 cranks or so.
Then I squirted in some 30 wt, about 3 full squirts from an old style pump oiler and tested again.

The psi came up 15 pounds to 155 after about 10 or so cranks.

Here's whats more, just for the halibut, I kept the tester on it and its been almost an hour and the pressure hasn't come down at all.

So what would this indicate?
Does it say that the compression ring is bad in #5?
Does the fact that it is holding pressure for awhile now indicate anything?

Update: After almost an hour, it has come down about 2psi.

My compression gauge has a button you press to release pressure, ie its holding pressure for a long period because of the release valve is closed not because of the engine. I could unscrew the gauge from the motor and the gauge would still read the highest reading.
I know with my 327 I had terrible compression on many cylinders, squirt of oil did help 15 or so which worried me, but then I bought an 'Air Hold Fitting Set (14/18mm) on ebay for $3.27 to see where the leak was, with both valves closed I could hear air leaking! Although I could hear some coming from below it also came from up top!! Pulled the heads and found some of the valves wouldn't seat well at all. Had them rebuilt and that fixed the compression issue completely! Went from 81-136 (cold) to 149-152 (cold) on all cylinders. I would yield higher #s if it was warm.

Doesn't your compression tester Have a schrader valve to release the pressure to test again ? If it does you are just testing your gauge. You need to do a real leak down test. Unless both valves are closed you are not testing anything.

OK, I realize that now, I'm an idiot. :o

But back to the real question;
15 psi after adding oil.

What does that indicate?
ring or not?

I ask because I'm about ready to tackle this problem in a big way and am trying to determine whether or not I need to do the whole engine.

If I can get away with just heads, I'll be able to also afford the tranny work I need done.

They say if compression goes up with squirt of oil then its the rings, unfortunately thats not always true! As in my case it was the valves not the rings at all. The Air Hold helped me determine that air was leaking past the valves, you should do the same to see if you hear any air leaking past the 2 closed valves.