Some post war Aux AF (later Royal Aux AF) squadrons had the aircraft in a painted 'aluminium' finish, others in standard day fighter camouflage. I'm not aware of any 'standard' RAF aircraft of the period, apart from perhaps the B-29 'Washington', being in a bare metal finish.
However, 601 Sqn was disbanded in May 1945, in the MTO (Italy) when equipped with the MkIX Spit, in camouflage finish.
The Squadron re-formed in December 1946, with Spit LFXVIe, until December 1949, when Vampires started to arrive. At this time, the codes had changed to the 'reserve' codes - RAH.
Are you by chance referring to the scheme worn by the BBMFs Spit? I believe this replicating a 'one off', for a record attempt, or air race, with the aircraft flown by the 601 Sqn CO at the time, when they were using MkXVIs, and not a 'standard' scheme.