Canvasback, thanks for averting the invasion. Thread went off the rails pretty quickly!
I do not have specific advice for entering/leaving with guns but good on OP for looking into it. In general crossing any border with a little advance research into the other country's laws, culture, and history is always appreciated by the locals.
Why do our comics move to US? Not just for the $ but also for the wealth of material.
https://www.youtube.com/watch?v=gFgPX0hnNfA