Okay.....6682 LE's built "from March 1979 {car number 492071), the last Californian car was 500344 (December 1979) and the last Federal car of all was 523000 (August 1980)". Just look at the last 6 digits of your VIN.
Can't really tell by LE options as some PO's have added them to other cars.....however, all LE's were black & the black painted by the factory had a tiny bit of metal flake in it where aftermarket blacks do not..so, it's easy to see if it's the original paint.....the LE front spoiler - black hard rubber, not thin fiberglass) - goes on over the valance, not in lieu of the valance.