all the Indian GP's i have owned were made by SIL and had offwhite/dirty white/grey white tank,head cowling,tool box and flywheel cowling. IT IS NOT the same as italian gps because i still own original examples of both.colour wisw erm ... cream with a few drips of grey in the mix maybe??!!
finish...hmmm...my guess is enamel with no primer.
id paint the tanks with grey white if i were you. i think maybe alwyn pushpaks and some viraj thingys may have had silver tanks and bits but the SIL factory mainly used the white internals....probably.

Alcoholic maniacs social club. out f@@k,out fight and out booze 'em.