I disassembled this old outdoor spigot to replace the stem seal and stop the slow spout drip. I can't see any markings on it. But the seal refused to slide out and from pulling, popped off inside the unit! I can reinsert the stem and the screwhead will go into the seal again, but not pull it out. It leaks more now, of course.
Edit: Well I tried getting the seal out using the water pressure itself, thinking it might blow it right out. That didn't work, but I did get shards of the old, deteriorated seal as it fell apart. Given where this seal is, even getting a replacement in there would be challenging. I'm not convinced it can even be removed externally. Tomorrow it's supposed to be very cold so the whole faucet must be replaced now.
Looking in the crawl, it was a 3/4" threaded fitting to 1/2" copper. I went to the local home improvement store and boggled at how few "wall hydrants" they had in this (apparently 12") size with 3/4" threads. The only frost-free faucet close to this was an inch shorter:
It took a lot longer than an hour. My propane torch was 20 miles away, so a proper copper alteration wasn't possible. A red brass 3/4" FIP to 3/4" close was used, making the whole thing about an inch longer than the original. The exterior mounting holes were also different, and I don't own a hammer drill and assorted carbide bits. I expanding-foamed the gaps and insulated the union. So yes, it's working and drip-free, but is not flush with the exterior brick. Now I have to go back down there in the spring and trim the 1/2" pipe so the faucet is flush outside.
Moral of this story: Just because you can do-it-yourself, doesn't always mean that you should. Yes, I saved money by doing it myself, but now I have to essentially re-do the job in the spring because I didn't have the proper tools.