Who makes this backrest?

My recently purchased 2007 Silverwing had a backrest at one time. The seat now has a hinged cover with a snap, that conceals a rectangular metal socket that appears to be designed to accept a 1" x 1/4" flat steel piece of bar stock. There is a stiffener bar that extends between the foam and plastic pan of the seat. I would like ti purchase the missing backrest, since it appears the installation has already been done. I've looked at the Utopia, but I don't think that is what was installed. Any help?

Hmm... Maybe be a Utopia backrest mount.
http://www.utpr.com/silverwingnew.html

Cosmic_Jumper is right. Go to the site via his link and look carefully at the installation instructions and it leaves little doubt. Nice work Cosmic_Jumper.

I will contact Utopia on Monday. As I stated, I visited their website and even downloaded their instructions. There are definite similarities, but the socket design is unlike anything on their website and unlike any other Utopia backrest I have ever seen. I’ve had a Utopia on my Goldwing for over 25 years and the backrest portion is the same today as it was then. I’ve never seen a Utopia that just slid into a socket. They all seem to hinge and remain in place. Maybe this was a sort-lived experiment. Hopefully, I can buy just the backrest on a rectangular bar and be good to go.

My butt pad was missing when I bought my used 2002 SWing. I've looked but can't seem to find one. Any ideas?