Akella sucks.

The model in this particular mod has been enhanced by me in terms of textures and the polycount.

This particular model has been made by RWS before Akella trashed it in favor of the current P3 retail dude model of their own. Postal 3 development is one of the most interesting pieces of a videogame design in history of videogames, at least for me.
If it wasn't for the Economy Crisis in Russia then the game would be good.

Also out of respect for Running With Scissors,
Buy POSTAL 4 or POSTAL 2 with Paradise Lost Expansion instead, seriously. Postal 3 does not exist, but POSTAL 4 does.
https://store.steampowered.com/app/707030/POSTAL_4_No_Regerts/

The character shown in the mod was ported within possibilities of diesel engine modding, made with znixian's model tool!
Installation: Drop the folder from the archive to your mod_overrides folder, example:

C:\Program Files (x86)\Steam\steamapps\common\PAYDAY 2\assets\mod_overrides

If you don't know how to install mod_override mods, please refer to this guide!
https://wiki.modworkshop.net/books/payday-2/page/installing-mod_override-mods

You'll find the Dude in the outfits tab inside your inventory.

Requirements for this mod in order to work properly:
SuperBLT
BeardLib
Legendary Armour Skins
Postal Dude's Voice by Rick Hunter for Bodhi

Enjoy! Masks are supported, however due to the small shape of dude's head most of the glasses will be a bit far from his nose.
Bugs: During my tests, there is a 30% chance that you will encounter a polygon that can stretch to dude's legs but most of the time it's invisible so keep that in mind if you're going to submit that as a bug.