Taking the upper and lower apart technically could do it but it's still risky.
I would take out the magazine button and I would also take off the pistol grip and buttstock. With all the parts off and the associated pins and springs out, you can also take off the take down pin, which would be wise anyway since it might fall off without the pin holding it in from the buttstock.
Then on your way in, stop by a gun store asap and buy a BB before you get caught.
As for magazines, if you disassemble all the components, you can still bring in "kits" but you cannot assemble them inside the jurisdiction into a new magazine. You can only use your own kit to repair your existing magazines, which you have none, so it's just a kit.
Guns! More guns! I need more guns!