I don't have the information you need, but you might try posting on the kitchen forum, too. They're always talking about vintage appliances, especially sinks :)

Porcelain sinks are easy to find in Boston and there are many good repair shops but I would try to find one that doesn't need work.

It would help to know where you are located.

Here is a link that might be useful: This Old Tub and Sink

As an old house lover....

If you can't find a vintage sink in good condition, just buy a new sink. The vast majority of refinishes are substantially less durable than the original. The kitchen sink takes a ton of abuse, so durability is critical.

Thank you for your responses! I will post under kitchen as well, thank you! Also, I live in SC... and I will start looking for one that does not need work. Thank you!

If you have established plumbing supply outfits that have been around a long while, they typically have a large inventory of vintage sinks for sale in various conditions. We got some nice sinks in my wife's hometown awhile back.

You need to be aware that most of the porcelain 'refinishing' is a coat of epoxy based paint that is NOT very durable.

It barely makes it in bathtubs, let alone a kitchen sink.

Many years ago there was one company that could re-porcelain iron items.

Blast it clean, apply porcelain slurry, fire (around 2000 F to 2500 F) but they are long gone.

There are still new porcelain sinks that are nearly identical to the old ones.
The day of the double sink with double drainboards is probably gone though.