dabhand, it depents on the year the vehicle is you want to paint.
In 1941 the Afrika Korps used the common Panzergrau from Europe, then RAL 7008 (khakigrey)
From March 1942 onwards RAL 8020 and RAL 7027 was used (also RAL 8000) Thats brown shades.
Best you ask the internet about the german RAL color system.
I know Testors has some good matching colors in their range (afrikabraun).
Hope this helps?!