Help finding mounting plate/knob

[David Duke]

I know that I've seen these but can't remember where, I've look at Woodworkers Hardware, Van Dykes, Rockler, Woodcraft and a couple others but haven't been able to find it , not saying they don't have it but can't find it. The finish is a really dark antique brass and as show the plate is about 4 3/8" x 5/8". I appreciate any help in finding a source for these.

135750

Thanks in advance,