ftr: they did NOT come in blue OR yellow
there have been many custom paint jobs over the years, including mazda rx7 green (wild), bright orange (gross), silver (schmick), lambo purple (pink lol) and then theres the crazy japanese multi-coloured ones... the list goes on...
but the only official factory colours are:
KH3 = black (the only colour that was available throughout the entire production and hence the most common)
531 = white (late models only)
KJ7 = ivory (early models only)
AJ4 = red (early models only)
TJ1 = grey (early models only)
FM0 = turquoise (special commemorative)