I also didn't say welcome to the USCA forum. Note, looking at Ambassador 5000 reels on eBay is a good way to see what the original reel had. If you want to use a really old reel that you can not get original parts for, that one is as good as any and that is totally up to you.

It depends on whether you want a reel to fish with or a reel to look at. You can find numerous Abu Garcia reels that were made in Sweden like their 6500C3 reel and be much better off. If it were me, and I wanted a reel to fish with, I would sell that reel on eBay for parts or a vintage reel just missing a handle and then use my profits to buy a decent bait casting reel that wasn't so out of date. I am sure you could find some newer model parts that would fit it but you still end up with an old reel and don't really know its condition yet. That means finding the correct parts will be hard to do. If you look on eBay, the Ambassador 5000 reels are selling for between $100 and $2500 dollars, most toward the higher end.

The main problem you have is that you have a collectors item.

Abu garcia ambassadeur 5000 schematics