Looking at antique inkwell sets they often come as two inkwells on a stand, just wondering if there is a particular reason it would've been common to buy a pair?
Sorry if this isn't the right sub so please redirect me if needed.
I don't have an answer to your question, but there is a fountain pen sub that may be able to help you. Look for r/fountainpens (I'm on mobile or else I'd link you to it).