I haven't fished Falcon but I hit Amistead periodically. I stay out of Mexican waters. I have friends that love chasing the Falcon lunkers. Are you dragging a boat , banking it or getting a guide? Do your research. I don't go to Mexico anymore, I wouldn't advise it in any way shape or form.
I go through Border Patrol check points all the time with out issue or being asked anything other than citizenship and destination. I have no idea on RX concerns.
Time your trip with a lunar table and tear them up. I am a salt water nut. I hit Port A and Port Oconner regularly.
What time of year you looking at? If you're anywhere near we can wet a line a drink a cold one.
2014 Silverback 29RE, 2014 Ram 2500 CC 4x4 Hemi 6.4 auto w/ airbags, B&W Companion. Saltwater boats and rum like any good pirate.
Loose the 2nd and the rest will follow.