Why does sometimes the RX-78-2 have a white V-Fin while other times it's yellow?
In Yas's watercolor pages in Origin it's always yellow until the upgrade. The original tv design is supposed to be white outside of animation errors though.
The origin design is the only version that it's consistantly yellow.
Likely because a dark v-fin would have looked like crap. It wasn't on any of the MSV or MS-X Gundams.
Zeta created a lot of the long running standards for MS design since it was the first all new work created with the proper intention of what they were doing, besides the OVA RX-78s white v-fins and yellow eyes basically went extinct until Turn A. (it's interesting to note that only Strike, Freedom, and Strike Freedom have yellow eyes in SEED, by the way)