Actually there's not that much of a cost; what's required is time to do some research -- or access to a good knowledge base.
Hank's truck pictures is a good source. Another good source is the 1/87 Vehicle Club. They can usually help you with a lot of information (far more than you ever wanted in some cases ![Wink [;)]](/trccs/emoticons/icon_smile_wink.gif)
) about trucks and truck lines.
The Macks are easy. While the Mack website says the B series was introduced in 1949, actual first registrations didn't start until 1954, so 1954 is usually accepted as the introduction date. The R replaced the B in 1996 and, in various forms, stayed in production until 2003. The prototype for the Athearn model remained in production through the 1980s when the cab was redesigned.
Athearn's Ford C is good from 1957 to 1990 (some were produced so late, they were registered as 1991 models). The only exceptions are the model years from 1958 to 1960, when the C had quad headlights. Badging changed in that period, going from the Ford crest to the blue oval, but that's a nit you can pick if you want. The Ford C pumper truck is a post-1986 truck because of the KME rescue pumper body. The rescue truck is a based on a 1967 Ford C with a Gerstenschlager body. As best I can tell, the Telesqurt's prototype is a 1980 truck, though similar trucks were built from 1972 (when the Telesqurt was introduced) through the 1980s.
The CMW White WC22 was produced from 1950 to 1959. Their White 3000 COE is a 1953 model.
Trailers changed somewhat over the years but major changes came in the 1980s, when the laws governing trailer lengths and weights were changed. Once again, some time spent on Hank's website would be time well spent.
I know at one time we discussed doing a reference for trucks on the 1/87 Vehicle Club website, but it involved a huge amount of time, which no one ever seemed to have. Perhaps this is a project that could be revisited.