Nice pick up. Hope it was a bargin.
Well about its authenticity to be a 1/1..................
As it says, it is an after market card post production card......ie these people acquired the card after its production from the market, kind of like UD buybacks.
And as it says, they (the people stamping the card 1/1) are not associated with the actual card producer (Topps).
So............for example.................I could open a pack of topps, got that card from it, used a foil stamper saying '1/1', stamped only one of that particular card, made a certificate saying what I did and guaranteeing that it is a 1/1, put some sort of stick on it with a serial number corresponding to a serial number on the certificate..................hey presto..........you've got yourself a 1/1 card.
Sell it on EBay, its easy to get an audience.
SOme people who would do this kind of thing, are those who were maybe ripping off the Fleer auction cards ans stmaping them with theor own numbers. They would have the right equipment to do this sorta thing.
Ersk