Brake Question: 1991 OCC has no star adjustment hole and grommet

I was replacing my front disc pads and figured I'd pull off the rear drums and inspect the shoes.  They were fine, but I found one cylinder leaking, so I went ahead and replaced both of them.  The fluid was nasty, so I bled each wheel.

Everything is working fine.  

I wanted to adjust the rear brakes, but low and behold, there is no hole in the plate to access the star wheel adjuster.  Actually, there is a hole, but it has a small cover welded on that I'm assuming I could smack with a hammer and screwdriver to remove.

If I remove it, I'll need some grommets to seal up the holes after I'm finished.  Where to find those?

Should I even bother?  I've done the reverse and brake thing to get the auto adjusters to kick in, but I'm not so sure that is  sufficient.  How do you even know if your rear brakes are engaging?

Any advice from someone who's been there and done that?

I just did brakes a couple of weeks ago and the hardware kit (springs, etc.) came with new rubber grommets. I think I got the kit from Rock Auto.

The star wheel will adjust every time you back up a foot with the brakes on, until they are fully adjusted. If you have an open differential, you can lift one side in neutral, and turn the tire by hand...if the brakes are applied, the wheel should make the wheel impossible to turn. If you have a posi, lift both wheels. You may not be able to tell if one or both brakes are working with the posi. It will take about 65 ft. lbs. of torque to turn one wheel with the posi.

No hammer I've ever tried to hit that stupid little welded cover ever made it come off. I always have to drill them out.

I just installed a replacement rear in my Roadmaster the other day, it too had the oval "holes" welded up, weird! I drilled them out and cleaned the holes up with my dremel.