There are about 15 small BWS and each of them got 3-6 of those jackets. Then you have BWS Harajuku, Bapexlcusive, BWS NY, and BWS London which probably got slightly larger alotments. Mabey 15 at Harajuku and Bapexclusive and 6-10 in NY and London.
Very rough guesses but for a Jacket like that most BWS don't even get a full size run. They might get like 1 Small, 2 Medium, 1 large and that's it. And for any single color of any single teeshirt design they don't get much more than 5 peices at the regular BWS and probably less than 15 at the bigger places.