No.
In SBProPE, only the skins are moddable, not the models. This is a texture for the "Uniform1980US" Infantry model. The firearm is modeled and textured separately.
Without looking, I'm not sure which flavor of M16 the US1970 nationality uses. If it's the A1, you could conceivably rename and install this skin in that mod folder, as the two use the same troop model (but slightly different normal maps). The obvious downside would be that vehicle skins would be Seventies rather than Eighties.
As for me, I prefer to "squint harder."