I think Mark Murphy was the first, or one of the first to sell these, and advertised them in SCD. He said they were restocked Topps cards repackaged by a 3d party and sold in retail stores. But he did not or could not name the retail stores or the 3d party packager, and the dates that the packaging supposedly took place have varied ( 60s, 70s, 80s).
There has also been disputes about which Topps issues were initially involved. I think Murphy originally sold 54-63. Later, earlier and subsequent years appeared. Even if his story is true, there is no doubt someone else is continuing the process.
Some people claim to be able to tell the "originals" from the later productions looking at staples and the configurations of the packaging. The folks claiming this are usually selling them.
Here is some correspondence I had with Murphy and his partner about them
