It certainly is an interesting find. I am at the moment just restoring one which was in similar condition. I have known this Jeep since 1968 and in those days it was quite common to find such jeeps, usually on farms or for sale in the local paper - in my time I have had a couple in this condition.
The British Army usually would rebuild their jeeps in their workshops, at which time I imagine they were just completely dismantled, repaired if neccesary and overhauled as required. Mine is a Ford GPW, chassis no: 202055. DoD 5-22-44 It had been rebuilt in approx. 1952. It was then fitted with a repaired body ~ 187186, or Jan 1945. There was evidence that the left side rear panel had been replaced as the section was fastened in with small rivets.
The post-war colour scheme was the dark green - the same as all the other vehicles in the Army, and the same as yours. FWD Motors was a well known supplier of ex-military vehicles, as was Metamet - who did the work on Half -Safe after Ben Carlin had crossed the Atlantic. They were situated in Daleham Mews in North London, and were for a long time suppliers of the spare parts we needed - no repros in those days!
As I understand it Airbourne Jeeps were modified as required from standard issue ones, and the mods varied according to each units needs. During the War Popski was issued with jeeps modified in the workshops in Egypt - as was the SAS, and for example they were armed with a variety of weapons including captured Italian ones. The Vickers was chosen because it was available and had a high rate of fire, replaced later with Brownings.
It could be that your demountable steering wheel hub was fitted simply because it was available - They were not common by any means but I have come across a few.
As you state your intention is to rebuild it as a representative Airbourne Jeep - then go to it - I might be wrong, but as far as I am aware there was nothing written down as a specification - they were modified for the job in hand. There is plenty of reference for you to follow as a guide.
If the Army had rebuilt it ,there should be a brass plate, usually fitted inside the front wing by the battery. Or possibly the 4 mounting holes are in evidence. The plate was
120mm X 90mm and gave the dates and depot where it was rebuilt, though often they were removed. Also on this plate would be the later British Army registration number, eg 33 ZC 80 - from which it is possible to find the Key Cards showing some history of service.
I took a number of photos of mine before I dismantled it, and if you are interested send me your e-mail address and I will sort them out for you
Exeter Devon UK
FORD GPW 202055 DoD 5 - 22 - 44 Serial# 20534360
MBT # 25553 DoD 4 - 43
MATCHLESS 1944 G3L C5806205 (Ex 33 ZC 80)
Piper Cub 1944 L4H 480015 G-AKIB
1942 CHEVROLET G506 CARGO. #2NM 213219