If the harness is "specific for 49", there is nothing to worry about. Colors not mentioned in 1949. Colors/tracers/cross tracers showed up in 1950, but flaky. The modern colors started to show up in 53.
Commentary:
Chevs of the 40's has two harness for 49. One @ $187 and one at $815. You don't accomplish anything meaningful by buying a "specific" harness except to spend a lot of money for nothing. The $815 is cloth covered or cloth loomed wire and is outrageous in price. Unknown insulation quality, abrasion resistance, heat resistance, environmental exposure testing. The $187 is uncovered modern plastic wire, same as a Speedway for example. Yes the terminals are crimped on and the wire lengths are correct. Nothing special about that. That doesn't create "original".
When "restoring" our old trucks, many say they want to keep it "original". There are many folks who start thinking about safety in todays world, highways, speeds, thousands of other fast drivers, dangers of getting stuck on the road/reliability. Original is carried TOO FAR unless you are going to use the truck on a limited basis.
Brakes, tires, steering, differential ratios and WIRING were all designed for a 30's, 40's and 50's world. Designed with the available knowledge and materials. All of the aforementioned systems need upgraded and do not really affect any normal conception of original. (the ratios can be an exception if performance is OK). The addition of turn signals is mandatory. Repeating some of the wiring "mistakes" of those eras is not prudent. I see that Chevs of the 40's used some fork tongue terminals in their harnesses, so as to be "original". An example of continuing a bad idea.
An upgraded harness is better in many ways than what the inexperienced electrical engineers did/used. There are so few wires in old trucks that with a little help, anyone can wire them. No soldering is necessary, just good crimping and some shrink sleeve to attach the necessary ring tongue terminals and/or connector contacts. Cut the length, route and tie up.
In the end, of course, it's up to the individual. But at least be aware of the aspects of "original syndrome".
