This gift was given out via 2 ways: a lucky draw, and via a free gift for NTT Flets (a Japanese fiber internet) users who signed up for the gift.
For the lucky draw:
There were 100 winners per Festa 2005 location, and there were 9 locations, so that's 900 winners from the drawing
For the NTT Flets members:
People who used NTT Flets were able to sign up and receive the Wobbuffet for free without having to be selected, and there's no known number for how many people downloaded it while being a user of NTT Flets. So the amount in circulation are unknown.
This gift was based on the live-action Wobbuffet that appeared on the Pokémon Sunday TV show.