There's really two options you have with a sunroof (like you couldn't have figured this part out on yourself)-
1) Keep it
2) Ditch it
I'm not sure on the availability of NOS sunroof parts, but that doesn't mean that you can't go through and clean up the sunroof you have now. I know I have two of them and the seals on them actually seem to be in decent condition, especially considering their ages.
I opted to go for option number two purely because I didn't like the look of having a sunroof. Mine didn't leak and was properly installed. For patching them you can go with a metal patch, or a fiberglass one. Again, I'm not sure on the availability here, but I have seen entire roof skins done in carbon fiber so I'm sure that there's something out there to patch a sunroof with.
I opted to go with the metal patch and got mine from my parts car that had a straight roof. I just cut the entire skin off so I was able to lay the entire thing over my roof and trace the piece that I needed from inside to cut for a perfect patch panel. From there it was just a matter of tacking and then stitch welding it into place and then smoothing everything out by grinding the welds down and then skim coating with a layer of filler. Unfortunately, it rained on my filler and now I have to do it all over again
The hole is definitely patchable (even if you need to clean up the hole with a clean square cut a clean skin from a donor car can be used) and I wouldn't let it shy you away from a good car in the least!
Hope this answers your question!
lmk if you would like some pics of my patch job