They all didn't and still don't have Winner stamps on them. Like full foil Electabuzz Best promo came stampped and non stampped. All the special energy holo promos came stampped and without a stamp. They were given out in tournaments dependin on attendance. Many players=more turnament top players got the winner stampped version of the card and the rest got the non stampped version.
I think the last one that got out (before nintendo took over) was Rocket's Mewtwo. I heard they never intended it to get out with a winner stamp on it, but some TOs got them anyway with the winner stamp. The're not rare to find though but sell for a bit more than the Electabuzz and Rocket's Hitmonchan that came out before it.
Some of the cards were printed with winner stamp only, like Rocket's Sneasel and Rocket's Scizor. I have never seen them or heard of them being without the winner stamp.