Having done some research previously in to the Chipmunk, including a fair amount of historical material, I am pretty confident that the cockpit interiors have always been finished in black.
The only noticeable recent change that I have seen is the Shuttleworth Collection's Chippie finished to 'represent' the bright yellow scheme of the RCAF. '671' is actually a fictitious serial and the aircraft is registered as G-BNZC. It was never in RCAF service (wrong type of canopy for starters ...) but I suspect the scheme was chosen for being bright and attractive? Anyway, it is the
only Chippie cockpit that I have seen done in something other than black - it is a light blue-gray throughout, including cockpit sidewalls and floor. I am not aware of any actual RCAF Chippie ever having had cockpits this colour.
See
here and
here for example photos.