I copied this from a 10-year old thread on Luftwaffe colors at WW2aircraft.net, who in turn copied it from another thread elsewhere (threadception?). Apparently it comes from David Wadman, who's authored a few books on that very subject so I'd reckon it's backed by some solid research. Here you go, hope that helps!
Beware the early/late split for 02/66. As part of a discussion elsewhere about early, BoB-era Ju88 interiors, which were certainly RLM66, this contribution was made by Dave Wadman regarding Bf 109’s of the same period.
“In brief, research to date by my colleagues and I along with photographs and the information contained within copies of the relevant RLM Messerschmitt documentation in our files identifies the basic cockpit colour for the entire 109E, F-0 and the earliest F-1 series as 02 with the instrument panel in 66 although grey 41 is also mentioned in one reference to instrument panels fitted to early E-1s.
However, while it is true that some E models did feature cockpits finished entirely in 66, this was due to which particular sub-contractor (e.g. Arado, Fiesler etc) built the airframe (regardless of sub-type) and not because of any directive, theatre of operation etc.
Photographic evidence of 109’s brought down over the UK during the BoB where the interior of the cockpit is visible, clearly show that, while the sidewalls, seat etc are finished in 02, the cockpit sills and sloping area immediately behind the pilot’s shoulders was finished in a much darker colour, which was, in all probability, black-grey 66. Logic dictating that it was likely carried out for two simple reasons - to eliminate glare and to avoid compromising the dark(er) upper fuselage camouflage of the aircraft when viewed from above. Additionally and just to confuse matters further, several E variants brought down over the UK which bore 02 finished cockpits had very dark coloured floor panels suggesting the use of perhaps 66 or even black for these areas.
Interestingly, every enemy aircraft that was brought down over the UK was extensively photographed in situ, the first being four basic views of the front, rear and port and starboard sides followed by areas of interest such as crew/cockpit areas etc. In such photos of 109s where the light grey (02) interior of the cockpit is clearly visible, several have the upper areas finished in a darker colour as mentioned above with a few, as also outlined above, having dark painted (i.e. 66) cockpits. This same is true in extant photos of many of the 109Es brought down, captured etc in the Mediterranean theatre, which, while retaining a basic 02 cockpit, have all areas above the pilot’s, shoulders painted in 66 or similar dark colour.
As far as canopy framing goes, that for the early rounded style was generally finished in 02 but according to recent documentary evidence discovered by German and Dutch researchers, the heavier framed canopies were painted inside and out in 66 at the source of manufacture. The exterior framework often being left in this colour rather than being repainted to match the surrounding camouflage finish; this would then be the most likely explanation why many 109s with the heavier framed canopies are often seen with the exterior canopy framework much darker than the adjacent camouflage colour(s).
For all subsequent Bf 109F, G & K variants with the exception of a few of the very earliest Bf 109F-1s, the entire cockpit, including seat was finished in 66, the same being generally true for all variants of the Fw 190 excluding the very early V (prototype) airframes.
As a broad rule of thumb, 02 as a cockpit finish was ordered replaced by 66 in November 1941. However, if your chosen subject is to have an 02 cockpit, don't worry too much about the variety of shades of this colour available in model paints as the same inconsistencies occurred even with the real colour which led to the RLM sending out advisory notices on several occasions between mid-1941 and early 1944 quoting that no concern should be raised about the colour differences between batches of 02 citing such things as quality control etc, etc."