I have a a faucet that leaks a bit from where the valves connect to the spout, and the threads where the aerator goes are badly worn. I was wondering if I can replace just the spout. It looks like screws in, so I should be able to, but I'm also not sure where I'd get a replacement. It's an old style (70+ years?), and I'm pretty sure it's an old faucet. Would most large home improvement stores carry a replacement, or would I need to confirm the thread size and special order it?
You might get away with unscrewing the spout, cleaning the threads on both the spout and faucet with a brass brush (just to clear any accumulated crud, especially if you have hard water), wrapping the threads with thread tape, then tightening it back on.
If that doesn't fix it, odds are good that you'd have to replace the whole faucet. I'm not sure where you're located, but that type of faucet isn't common at all in the US and wouldn't be available at a large home-improvement center type of store. You might be able to find something similar at an actual plumbing supply house. They may have something in a commercial line that would fit. If you go that route, either remove the faucet from the wall and bring it in with you, or take good pics with a measuring tape across the top of the plumbing stub-outs so they can help you find something with the right spacing.
I believe that you may be able to find replacement for your wall mounted faucet spout. These are common in commercial or restaurant applications.
I found this one but i do not know if the threads are compatible. If you live in metropolitan area you could take it to a dedicated plumbing supply house and see if they can match it.