At least I got the spelling right this time!!

I am nearing completion of my Panzerspahwagen however a couple of queries....
First, there are smoke dischargers mounted on the front. The instructions state to paint in panzer grey as I have done for the remainder of the vehicle, but it just doesnt look right. Would the disharger units not be a different colour eg, a drab of sorts?
Secondly, I havent got round to washing yet (it will be my first time) but for parts such as the jack and fire extinguisher, will washing be sufficient to 'bring them out' or, as in the case of the dischargers, should I paint these a different colour also?

Thanks in anticipation.