Polaris-Metalic paint code 060 was used from 1970 onward for the following models:
R45, R45N, R45T, R45TN, R65, R65T,
R65LS, R50/5. R60/5, R75/5, R60/6, R75/6, R90/6, R65 Mono (all), R65RT Mono, R80 Mono, R80RT Mono, R100/7, R100/7T, R100T, R100RT, K100, K100LT, K100RS, K100RT
ColorRite can provide custom rattle can paints. You may need to make contact and see what they can do for you. Some of the later BMW models have the Polaris color you're looking for. And since their motorcycle years do not go far back enough to list your scooter, ask about the K-series years.
Good luck with your search. Be advised that paints do age and change their "stripes" as the years go on. As such, a perfect match may not be possible. Close enough for gubmint work.
ftp://http://www.colorrite.com/