I want to point out that unless you are bringing your airsoft gun to the US for sale, it does not require an orange tip. The orange tip required for transport is covered under the commerce section of the United States Code. The US Department of Commerce does not have jurisdiction over personal use and transportation.
As a note, I fly with airsoft guns, either personal ones or training samples, on a regular basis, and they don't have orange tips.
Note that this obviously has no bearing on trying to get it BACK into Canada! Yeah, rentals would be needed, like with OP Pine Plains each year.