My guess is similar, but not the same, as the chemistry of paints has changed.
If I recall, even the First Edition SRT-10 Coupes were SLIGHTLY different from the original GTS Blue. The SRT guys made a point by showing some of the VCA officers a series of "GTS Blue" tiles and asking if we knew which one was the "old" versus the "new".
What I noticed was the metallic flakes were actually finer (smaller) in the new formula.
Considering that yellow is not a metallic color... the difference might be negligible (unless SRT actually selected a new yellow altogether).
Jonb?