Although I cannot say for sure they were taken from the same master mold, it is certainly possible as the overall size and the tail piece are exactly the same. They also have the same tiny imperfections on the bottom of the feet. The only difference is the vinyl of the flesh bootleg is very thin and just feels so cheap in hand, while the vintage j-tail is thicker, dense vinyl and also has a strong, musty odor. Kaminaga-san and Nishimura-san both mention using the original Marusan master mold to create their modern j-tail reissues in the late 90's and early 2000's that first started out with the original larger j-tail size sculpt with blank feet like this, although both Marusan and M1GO eventually went on to retool their Gojira reissues. Marusan uses a slightly smaller sculpt with different custom engravings, while M1GO used the original large j-tail sculpt with a custom Bullmark engraving.