Value range if it was all original could go from 1k to numbers that would make your head hurt.
Since it isn't, more information is needed. Pictures would be great. Is it a factory barrel? If so, how old? Did the factory do it or a gunsmith in a shop? What length is the barrell? What kind of grips? How much finish left? Any engraving? What markings are on the frame, barrel, under the grips, on the back of the grips, etc.?
IMHO, worth spending the money to get it lettered. You might be able to find a period correct barrel and get it back to its original configuration. Maybe it started out life as a 38 WCF and that's why it got a 38 spl bbl later in life.