If you found a NOS one you would probably want to rebuild it anyway since the seals would be dried out. Had mine rebuilt by OldAir. Be careful pulling out the temp sensor, it’s a capillary tube and once cracked or broken it’s done. On the other hand the valve functions perfectly well without this early and not so effective temp control function.
I have one that I picked up a while back. Came with a receipt that it was sent to Fusick back in 2000. It was rebuilt but I have never had it in a car to test it. I would let it go for 75% of whatever they charge for the rebuild now.
If you cut the capillary tube and take the valve off it’s easy, which is of course sacrilege. If you want to keep the capillary tube in place on the valve you need to remove the heater box with the heater core as the capillary tube is behind the core and you can’t get it out without removing the heater box from the eng compartment. I other words, a pain in the ass.