Actually the foldildo comes with the YF19 on its second release. I get the impression that the Yamato marketing team are a bunch of scatter-brained people who are very unsure about what they want to bundle with their main products all the time... remember - this is the '21's first release... by right, we should have gotten that clear stand for the '19's first release as well. Same goes for the VF0's FPs - bundled together and sold as a set, but not given the same treatment with the 1/60 YF19. Same goes for the side parts that comes with GBP set... they should be included in the FASTPACK set as well if not bundled together with an alacarte 1/48 VF already.
Of course, not that it's a BIG deal in the scheme of things, it's just happened that they have no such standards and aren't organized at all.