If you are talking about RNAS armoured car squadrons they wore both naval and army uniforms at varying points of the war.
Early photos at Dunkirk show both naval and army uniforms. Most of the early UK based shots seem to show naval rig, in particular those associated with AA duties.
By the time they Locker Lampson had deployed to Russia it's all army kit.
I'd strongly recommend picking up David Fletcher's 'War Cars British Armoured Cars in the First World War'. It's packed with contemporary photos.
A quick survey shows
Wearing Naval Uniform:
RNAS with MG armed tourer in Flanders circa 1914 (p13)
Talbot (undated but presumably late 1914 early '15) in mostly naval uniform (p15)
3pdr lorry photographed at Dunkirk (p16)
HMS Aniche, modified Admiralty Talbot (p17)
Rolls Royce of No2 Squadron RNAS at Southwold Fire Station (p20)
Seabrooks at Portholme Aerodrome Company, Huntingdon. (p22)
Seabrook with a mix of Army and Naval rig on p23. The naval officers are wearing Army tunics with RN rank insignia, The POs appear to be wearing straight naval kit.
Scottish Lothian and Durham Churchill AA trucks at the RN dockyard at Forth ( both p32)
Most of the rest show army uniform with a few mixed items including one of an early Wolesley in Flanders with it's crew in army uniform. There is an interesting photo of an RNAS Rolls Royce pom pom at the Barlby Road depot of the RNAS and this shows the crew in army uniform.
There are various photos of RNVR UK based AA units all show naval uniform. (p 61, 62, 63)
All of the photos of I've seen of Locker Lampson's Russian Armoured Car Division show Army uniform
Hope that helps.