Help identifying dealer from old flip

Hi all,
I recently purchased a coin on eBay that came in this flip. I did some googling and couldn't find any dealers with this name. Not sure what the vintage is of the flip itself -- it does not look particularly old, but it definitely as that old library smell to it.
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I dunno. But google image search found this

Mr_Spud
The envelope is 1963 or late
He advertised in popular mechanics as far back as 1951.
I did some sleuthing and it looks like he also published price guides for his buying, this is from 1964: link
The other side of the flip says that the dealer was in operation for "a half a century". I guess we may never know exactly when this flip is from!
I recognize the name but have never done business with him.