the Brougham Ciera for 1983, the one you have, is one of 90,307 made; split further into 17,088 Coupes, 73,219 Sedans, no further split for 4 or 6 cylinder models; came with either the 2.5 liter RPO LR8 8.2:1 Compression ratio 4 cylinder engine (Iron Duke) or the optional 3.0 Liter RPO LK9 8.45:1 Compression 6 cylinder Buick v6 engine; all had TH125-C 3 speed automatic with lock up converter, does not mention if 4 speed manual were available for the Brougham; JA1 brakes, options are what makes them different, for example, mine has the 45/45 split seats with storage console, AMFM Cassette player with power antennae, and so on; the Brougham was more numerous than the LS ; but i dont know if the ES is part of the LS or Brougham lineup, however being a 27+ year old car, there are not many 1983 Olds cieras or 1982 cieras out there left due to rust, scrap, and accidents. I think you will find
A-Body.net to be of tremendous help in figuring out what you have for options and repairs and parts; do you have pictures or something? it may not sound rare on the face of it, but honestly, there are so few of the pre-86 Cieras and other A-bodies that they're pretty cool in their own right. if you can, there should be a folded piece of paper between the yellow foam and the metal net underneath the front passenger seat, that is your build sheet and yu need to be extremely careful taking the paper out, it is a 28 year old paper.