Hi Russell
The cars are sisters...same colour codes throughout, including colour of the soft top (assuming you mistyped the code as there are no 400s it is 737 brown)
I am not sure about the originality of my fuel cap, but judging by the general wear on the key I would suggest it is original, although I have seen a few designs on pagodas including knurled edges, MB logos, keys and no keys. For security you might want to get a locking one from hh-sls?
Regarding the dash, I don't have a picture at hand, but they all had a clock, on 230s they were 'electro mechanical' which basically means they were powered from the battery, but only in so much as the battery wound the mechanical aspects of the clock up. Time keeping s very bad on these and mine gains around 20 mins per day! Some have sent their clocks way for conversion to quartz keeping the old face for originality.
Regards
Mark.