Crap! That was about 70 miles from me!!
Did anybody save a pic of that auction? The box for that would be the same type box Ruger would have shipped theirs in.
I'm pretty sure Seymour Smith was making braces of the Ruger pattern long before Ruger ever made braces. I think Ruger purchased the rights to make the brace (or had them made for them by Seymour). And Ruger issued the design patent on it.
Weaselmeatgravy has a Seymour brace that has different parts on it including a slider that is flat and made of brass and a wood top piece. That tells me they were made long before Ruger made tools.
Chet15