Windsock Datafile 48 'Airco DH2' by B.J.Gray: "Factory finish of production DH2s was light grey for all metal and wooden components."
But I understand your confusion. On p.32: "In May 1916 instructions were issued from RFC HQ that all nacelles of pusher aircraft were to be painted dull grey. In the same month the RFC began painting the upper surfaces of its aircraft with pigmented dope (PC10), which varied in colour from chocolate brown to a greenish khaki. By June all the DH2 squadrons followed suit. No.32 Squadron, which did not arrive until late May 1916, had already applied the PC10 finish before proceeding overseas. The grey nacelles were retained, although later in the year some DH2 nacelles did receive a PC10 finish."
Photo 42 on p.16 of the Datafile shows DH2 7873 of 24 Squadron's 'C' Flight. Boelcke claimed it as his 24th victory after it was 'reported missing' on 14th September 1916 and he's standing on the aircraft's starboard wheel. The saw-tooth pattern on the underside of the nacelle and the large compass fairing was unique to 24 Squadron's aircraft. The colour of fabric flanks and nose/upper fuselage in this case appears identical, i.e. one colour overall - and therefore presumably light grey.
Major
Lanoe Hawker fell to Ltn.
Manfred von Richthofen's guns on 23rd November 1916; he was flying DH2 5964 on that fatal day. Study of photo 35, p.14, of DH2 6011 of 'C' Flight No.24 Squadron, indicates a darker dope on the fabric-covered flanks than the colour of the nose and upper fuselage. I believe it's likely that the former is PC10, the latter light grey.
I've been researching the Air VCs for years, with the idea of building a 1:48 model of the aircraft flown by each recipient during the action that led to the award. But the road to hell is paved with good intentions. One day I'll get round to modelling Lionel Rees' No.32 Squadron DH2 6015, honest . . .
Meanwhile, I'd opt to paint Hawker's 5964 in light grey with PC10 fabric flanks; it looks nicer than plain grey in my opinion, and who's to tell me I'm wrong?
Hope this helps - cheers!
Simba.