You can tell you have a S2 truck from the headlights and dash. Look up lrfaq.org They have a data base of serial numbers to help a person figure what truck you have. The parts catalogue for your truck are easy to find either pdf or hardcopy. Serial number for the tranny should be looking from the highest point on the transmission itself looking down to between the housing surface and the forward section of the transfer case. TeriAnn's Expedition Land Rover site
, I believe tells you what the serial number on the engine head means. Cant remember if they stamped the number 7 in the same place as they stamped the number 8 on later engine heads.
Might want to also join some of the local forums in your area as one or two are some of the oldest clubs/groups at the very least have people that have owned rovers since the 60's and and join the mendo email list, most members on that email list live in California.
Did you find a data plate on the bulkhead? Not uncommon for engines and trannys to be swapped out. Someone else can chime in but I think the orginal color for rover engines is light green or robins egg blue range.
From the fuzzy pic of your doors you look like you have S2 door hinges.