An untimely fix for a dated GTA IV bags mod from many years ago. The original replaces a kind of headwear (rags/bandanas), but the game always hides prominent haircuts like Afro, Mohawk, and similar. I had to spend about five minutes to make sense of clothes.dat and make necessary changes to it. Supports modloader and manual installation.
Drawback — unfortunately, I was unable to counter the issue of the base game where all fresh haircuts remove your current headwear. I couldn't find any related settings for haircuts, and I doubt that there's a way to exclude certain hats anyway. You'll just have to go to wardrobe and put your bag on again.
P.S. If you have custom clothes.dat then you can follow instructions from the last image above. Carefully follow text placement and insert the following into your clothes.dat: IGNORE bandana ENDIGNORE bandana