yes edward that sounds about right
I've seen some service manuals cost as much as $600 depending on the mfg and model machine.
kinda pricy isn't it? DOH! ;o)

to answer parkways question though,
the service manual does not contain any part numbers to speak of, you might see them randomly in parts of the manual but generally they keep the part numbers and diagrams of component blowups separate in a parts manual.

In the service manual you should have the diagrams, schematics and diagnostic information on all systems pertaining to that truck though.