Legally, buying, selling or owning airsoft guns apart from the clear receiver cansoft models or the few makes and models that have been specifically allowed is grey-legal. Technically they're against the law but as long as you're responsible with them the police usually look the other way.
The one group that is seriously against airsoft guns is Canadian customs, so I really hope that when you say you ordered a gun, you did so from a site here in Canada. If you ordered it from overseas or down in the States then it is highly unlikely that you're going to receive it. Customs will seize it at the border and destroy it, and you'll be out the money you paid for it.
As to sidearms. That really depends. Some places will have cqb pistol games frequently, in some there are pistol target shooting organizations. But mostly, people have sidearms as last ditch backup weapons and they don't see a huge lot of use. The 1911 is a great weapon, I have one myself, a KJW model. The problem with 1911's though is the single stack mags have a smaller gas reservoir and so can't fire as many rounds as the guns with double stack mags. That only really effects the models with metal slides though. So if you're going to be using it frequently as a primary then I'd suggest a model with a abs slide like TM or WA. It's a bit of a hit on the realism but is more reliable. If all you want it for is a last ditch back up and the occasional pistol battle then a full metal model would be ok, just stay away from the WE's, they have a bad tendency to rip themselves to pieces.