What are the major cosmetic differences between a GP38 and a GP38-2?
Also, can anyone recommend a good book/website to learn how to detail locomotives and rolling stock?
the GP38-2 has several differences - the sight glass on the engineer's side of the long hood is the quickie tell. the battery boxes are bolted on the dash 2 instead hinged.
i recommend getting the classic The Diesel Spotter's Guide from Kalmbach - try to find the 2nd or 3rd edition - this can be had for under $10.00 at any train show.
and then get Kalmbach’s Field Guide to Modern Diesel Locomotives to fill in the happenings over the past 30 years.