There are the old radio guys who seem to hoard NOS caps. You may want to check these guys to see if they have something that might fit:
https://www.vivatubes.com/ https://www.justradios.com/ Personally, rather than depend on the condition of a very old electrolytic, I'd probably rebuild "in the can" with modern stuff. Unless you're taking about paper-in-oil caps, I wouldn't be very sanguine about really old stock--they have a tendency to dry out even in storage. --Chuck