I don't know anything about this online vendor, but the local guy here who repairs Vikings says that Viking won't even allow him access to their parts. I don't know how long this has been case, but I would investigate anyone who claims that they have Viking parts. But there are feet out there that fit all kinds of machines so maybe that's the case with what you want.

This isn't about Viking or about the website you mentioned, but I searched for a long time for the big open C-shaped FM quilting foot I wanted. The one made by a big name machine manufacturer that would fit my machine was $22. The no name one I found with the right shaft length was $9, fits just right and works great! Why not give the one you found a try?

Kate

I've bought from a company with a similar name.
I was very happy with their service. I was looking for a certain foot and bought one they promised would fit made by another manufacturer. They were right and the service was great. I recommend calling and asking about the Viking parts you need. They are located in Atlanta GA.
Hope this helps you!

Here is a link that might be useful: Sewingmachine.com