Don't have access to my notes at the mo but at one point the colour of a oil bottle did matter, bottles filled with oil for cold weather conditions were to be painted green ( so perhaps the different colours of the plastic bottles was intentional rather than a accident of what coloured plastic was available ) I've had See through green plastic, see through brown and the pale/ dirty cream ones. I've a vague recollection that the pale cream ones were associated with the oil issued for the 20 mm AA.
I'll see what I can find when I can get to the P. C.
ATB
Tom