http://counterstrike.wikia.com/wiki/M60
http://images.wikia.com/cs/images/a/ae/W_m60.png
In general of you do add it you could make the M249 lighter & do slightly less damage while the M60 would have the same weight as the current M249 & slightly more damage. It would balance the game a bit more.
I can also create the drop, use, & menu models for it if you don't want to waste time on that.
Its a cut weapon like the gas mask idea of mine earlier but unlike that I cant simply make a new weapon with lua so thus im hoping that you will seriously consider adding it either as a buy-able weapon for T. team alone, both CT & T teams, or as a stand alone non buy-able weapon like the flame thrower, RPG, grenade launcher, exc.