If the price is right...
Well, besides making/soldering a steampipe, the owner could solder
a disk of brass over the hole and start from there. Run it like that
or....try to add a sightglass. If the proper parts show up you could
just unsolder the disk and go from there.
For me, the hook is the patterned base. I could live with no sightglass.
If the price is right,
Wayne