I asked Tomas Bouchal, TBmodels,
http://www.tbmodels.cz/index.html and he answered this:
"Hi,
I think, that Libor Matejka from Panzershop must to know colors best.
This is my answer:
I saw PRAM in khaki color only in new condition ( semigloss ), not weathered ones. Rust is not allowable too.
My friend use XF-62 Olive drab + Khaki Drab in 3:1 ratio.
On PRAM I saw nice winter camouflage made by watersoluble paints made by white color or in spring colors too.
There is Czech colors manufacturer too, he offer authentic acrilate color too. It is C20P ( Czechoslovak - 20 - semigloss ). It is recommended to try it on piece of plastruct sheet for the first, I think, that it is not bad color.
http://eshop.agama-color.cz/zbozi/3804/C20P-Khaki-5450.htmhttp://www.vehiclesmilitary.cz/index.php/component/joomgallery/120mm-minomet-pram/120mm-minomet-pram2-142#joomimgsome info in english about this watersoluble colors is here:
http://www.modelforum.cz/viewtopic.php?f=2&t=104763&p=1901961&hilit=khaki+tamiya#p1901961The PRAM is in 99% of year days only in standard khaki color.
Tomas"