I ment more like the 'testors decal paper' with an inkjet printer. I know it's only in white or clear, so it might not work well with the light stripe on dark body. Possibly some fine white gel pen work to lighten it up, but at that point you're almost back to free-handing it.
If you're ok with it not being the exact and perfect striping from the real truck, there are a bunch of "Model car decal pinstripe" sheets from a bunch of companies. Some are small due to 1/14 vs 1/24, but realistically lowriders, kustoms, and minitrucks tend to go BIG stripes, and your trucks pretty mild stripes. Do an image search.
I believe this is gopher decal
https://www.newcenturyhobbies.com/Pi...04_p/11004.htm