if there is one thing I have learned when dealing with vintage appliances, and that is you will always come across a part you need when you are NOT looking for it, but when it comes time to need that said part, you will NEVER find one without an extensive search!
That's just the nature of the beast when dealing with stuff that's 30 years or more old. The stuff's not made anymore. To one person, the parts are junk, but to us, they are gold. It's sort of a random thing is something crops up or not, you just gotta go with the (filter) flow per se. Good luck in finding your filter! no harm done!