Need Help with Clefairy (Error?) Card

I was just wondering if anyone had any info on this card. If you know how much it is worth that would be great, but I'm just looking for basic info on this card. It is a Clefairy holo from I believe the Base set, but it's got a small heart shaped stamp towards the top within a little circle. I pulled this from the pack and did not alter it in any way. Last time I looked I couldn't find anything on it, I did see someone on eBay was looking for it but that was from a couple years ago. I included a link to a picture of the card on my flickr account and tried to put it up here, but it's not showing on my computer so I don't know if it's just me or not. Any help would be great.

https://www.flickr.com/photos/mfridgeway/6753427865/

This is something I'm not really finding any information on anywhere at all. I'd ask the folks over at PokeGym. A sizable portion of the staff there are people who've been collecting, playing, and judging tournaments since the beginning of the TCG. One of them might know something.

Thanks for the advice. I will do that.

Since you posted this, there has been another user inquiring about this. I wonder if it was a stamp for QC at Wizards of the Coast. That or it could have been done before someone repackaged the card, as there were (and still are) some shops that have booster pack resealing machines. Was this the only rare in the booster pack you pulled?

I believe it was the only rare from the pack but I can't be sure. I pulled this maybe 11 or 12 years ago so my memory is a little fuzzy, but I do believe it was. If it helps I think I got the pack either at my local card shop or at Target.