How do I tell if a rim is beyond help?

Working on a 1976 wr360 basket case that I picked up. Looking at the back rim mounted on the bike without a tire. I have no side to side wobble but I do have an "off round" wobble ,maybe a half an inch. There doesn't seem to be any visible damage to the rim. Is this "fixable" with spoke tightening or should I be looking for another rim?

Thanks in advance
I'm sure there will be more questions along the way!

If it's a pretty smooth egg shape, and not an abrupt "hump" you should be able to fix it. But it can take some work. If it were mine, I'd actually loosen all the spokes and start over. Heck - if you have to replace the rim, you'll have to loosen them all, anyway, so go for it.

While they're loose spin the wheel and see if it's less egg shaped with the spoke tension released, and go from there.

There were a bunch of bent spokes so I took the wheel apart. Polished up the rim, stripped the hub. I'll order new spokes today. I guess I'm going to learn how to lace a wheel! Hopefully I can get it trued up. This is just the start of this project. I would like a rider when I'm done, not a show bike.