They have recalls on some smith autos for being dropped on the grip, and the grip breaks, the mainspring loses a mounting point, and the gun is unable to fire.
SouthpawShootr is right ... that was a long time ago, and the grips were changed. Also, the tell-tale "dimple" in the bottom of the grip may be located to either the "front" or the "rear" of the D-shaped hole in the bottom of the grip, behind the magazine well.
The very few S&W aluminum frames we've seen exhibit excessive wear just coincidently seemed to be pistols which were always pretty much "bone dry" regarding lubricant being present. Shooting an aluminum framed pistol sans lubrication, especially on the rails, isn't the best way to prolong the service life of a pistol ...
The rails on my issued 6906, through which I've fired somewhere around 15K rounds ... standard pressure, +P & +P+ ammunition ... don't appear that much different from pistols of the same age, carried by folks which only shoot 100 rounds per year because we order them to qualify.
Proper maintenance isn't a luxury, you know ... and proper lubrication is very important.
I have a friend who shoots box-stock 4003TSW's for competition, and the last time I spoke with him he said his pistols probably don't exhibit much more apparent "wear" than my 4013TSW ... and he's fired more than 25K through at least one of those pistols, while I've only fired about 3K through my 4013TSW (I don't shoot that one much).
I'm still trying to wear one out, but it's difficult to do when you properly inspect, clean & lubricate them ...