I haven't had any problems in carrying mine for years -- even when not being cleaned for many months. However, I haven't been in much dust. I have stuck w. superlube, and I think it does a good job of keeping out the dust, moisture, etc. I think, between the grease, esp. if you keep the muzzle covered, there's not much room for contaminants to enter.
W. that said, if you'll have to use GI/NATO ammo, I believe it's far too high in pressure for the pup -- a compact Glock may be a better choice.