Ah yes, the Type 79, again.
This time with the Centurion Transformation Kit.

Yes, most police and SWAT Teams in China are still using a gun that was made in late 70s.

The model was ported from a L4D2 mod with permission granted:
https://steamcommunity.com/sharedfiles/filedetails/?id=2833149185

Includes:
l4d2_mod\zzzs570\type_79_centurion_kit\l4d2_mod_type_79_centurion_kit.mdl
l4d2_mod\zzzs570\type_79_centurion_kit\l4d2_mod_type_79_centurion_kit_magazine.mdl
l4d2_mod\zzzs570\type_79_centurion_kit\l4d2_mod_type_79_centurion_kit_magazine_part.mdl
l4d2_mod\zzzs570\type_79_centurion_kit\l4d2_mod_type_79_centurion_kit_parts.mdl
l4d2_mod\zzzs570\type_79_centurion_kit\l4d2_mod_type_79_centurion_kit_sight.mdl
l4d2_mod\zzzs570\type_79_centurion_kit\l4d2_mod_type_79_centurion_kit_stock.mdl

Credits :
zzzs570 - Original creator of the model and the L4D2 mod.
NeoLin - Porting to Gmod and SFM.