Black with a blue interior isn't common, but I have seen a few. Can't say for sure if it was original or not, but it sure looked good. Only way to tell is with the RPO code [paint/interior codes], the build sheet, the interior broadcast sheet [interior options] or the original window sticker. Not sure of any other way.
The odometer is mechanical, it just keeps rolling over. So no there is no way to tell. if the digits don't line up properly, then there is a good chance someone has attempted to change the mileage.
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There is no such thing as Too Many Montes Member of the Motley Cruisers Car Club
The Monte Carlo I'm looking at is an 85 LS Black (Repainted a few years ago) With OD.. I believe there were two transmission options for an LS of this year did they both have OD? And which of the two transmissions are better?