I would say your right, At the time I'm sure they figured if you wanted keyless entry, they assumed you wanted every other option. But like you said, it makes no sense that most of the keyless entry trucks were 3/4's and tonners. Its goofy how they did it back then, its almost like todays trucks, where you have only the Silverado package, but you had LS,LT or LTZ for top trim. Its like my '88 Silverado is pretty much a base model, it came factory with just a base radio with no cassette, crank windows and manual locks, and my '92 Scottsdale is damn near optioned the same except it has manual climate controls, vinyl floor mat and two tone deluxe paint. Other than that, there almost identical.