Before doing "research" on a question, it is nice to be sure that the truck series/year in question is the one in the signature. It often is not.

Thanks for the confirmation - 1955 Task Force

I'll try to post/add 1955 (and 1956-59) photos/documents/videos with original tailgates (all unpainted, I will bet/speculate).

Check out 4:09 minutes into this video.
Same truck, different ad - 5:00 minutes

1956 Stepside tailgate attached below (no painted letters)
1958/59 Fleetside attached below (painted letters) - 1958 "model change" year (stated in ads)
1960 Stepside (painted letters) - 1960 "model change" year (stated in ads)
1959 Stepside (painted letters)

Questions about possible painted letters:
- bedside vs fleetside (which had no "CHEVROLET" on the tailgate in some years)?
- with RPO chrome bumpers (front & rear)?

Nonetheless, it is your truck. Of course, paint the letters as suits you.
Attachments
1956 bedside tail gate609516-870-0.jpg (153.42 KB, 242 downloads)
1959 fleetside tailgate.GIF (75.71 KB, 232 downloads)
1960 stepside painted letters.jpg (80.91 KB, 224 downloads)
1959 stepside painted letters.jpg (125.55 KB, 220 downloads)