The LeSabre came in two trim levels.
Custom was the lower priced model. Limited was the upscale one with more standard features like heated leather seats, heated O/S mirrors with LED turn indicators in them and leather wrapped steering wheel.
I think the “special” editions were regional plans. We bought a 2004 PGA Tour trim model when we lived in Florida. Had all the items you mentioned but had PGA tour exterior trim. (Golf)
(Town Edition probably was a take off on Town Car used by Lincoln.
No difference in parts other than trim. If you feel lucky, try to find a “build sheet” under the rear seat cushion in the padding. There’s also a vehicle specific decal on the driver door and another in the trunk compartment.
Any GM dealer can give you the full information on your car with the VIN.#
If your car is a LeSabre Custom, that will be indicated by the badging on the dash and trunk lid. It will be “LeSabre Custom”. The higher priced model will be "LeSabre Limited"
Also by the VIN # the 5th position will be a letter. “N” is lowline (“custom”) “P” is highline (“limited”)
There was only one engine, a 3.8 L V-6 (No turbo or supercharger available.)
By the way, If you think you want to add OnStar service, it is doable. If the original owner had the digital upgrade done, all you have to do is call OnStar and they can help set it up.
I think it is a real benefit that you should consider.
I hope I’ve been able to help.