new member-big mistake-need movement

[adavis3rd]

Gentlemen, here is the deal,
like an idiot, i purchased a rolex datejust case and band on ebay. thinking, due to my current financial distress, I could sell my Tudor Tiger Chrono and build a datejust and have a little money left over for some bills. Yes, I know now this is a stupid thing to have done, but my only recourse is to try
and complete the watch with all genuine and model/year specific parts.
so, i need a cal.3135 movement for an early to mid '90's datejust
case. The seller swears the case /band are genuine. once it arrives
i will have it checked to see if i made an even bigger blunder. Financial distress can make a sane person make un-reasonable decisions.
It gets worse: the case back is numbered 16200 which would indicate an
all steel watch, (which I found out after the purchase) however, the case has a 18kt gold fluted bezel and the band
is a two-tone jubilee-again, said to be genuine. Do I live with the wrong
case back? or do I change the bezel /band to match the case number?
Obviously, if the parts are found to be fake, I am out the money and life
continues. Any help is appreciated.
andrew davis