is my engine original?

i wasnt sure which section to put this in so i guess ill start here. i recently purchase what i was told was a 1977 kz650. after further inspection of the bike when i got it home i notices that my front break caliper was on the back side of the shocks and the clutch master cylinder was more of a triangle shape and with what research i had done, this told me it was a 1978. now the vin on the frame is KZ650D004155 and the vin on the engine is KZ650BE048186. again with what research ive done this is telling me the frame is from 1978 D1 model and the engine is from 1978 B2 model. is this vin information correct? the reason im asking is because ive have had major problems with the battery draing which i was not made aware of by the previous owner. the wiring on the bike is not so pretty so i think im just going to rewire it this winter but i just want to know what model(s) im working with...thanks in advance guys. this site has been alot of help so far:)

look at the left engine cover, if you see three screw heads around the "Kawasaki" you have a 77, if it is smooth around it you have at least a 78'. if you are having charging issues it is important you know which one you have as the 77' charging system is unique.
sounds like you have a 78

You are confusing me about a few things. 650's never had a hydraulic clutch, and if you have a D model then that has a rear disc brake, and the master cylinder by the shock is for the rear brake. The triangular shaped master cylinder is for the front brake and should be on the right handlebar. Clutch is on the left and cable operated, front brake on the right...

Why don't you post a few pictures of this bike, because it may have been rigged up funny over the years.

You are correct about the frame model year and engine model and year. Your engine has the later model charging system.