We were in Rocky Point in February. We got stopped. First, let me say, it was random and it was not an unpleasant experience. US Homeland security stopped us asked us about guns. Mexican border police stopped us. A random Agriculture inspection was done, very similar to other border crossings (Canada). They asked about, dog food, dog rabies paperwork, meat, poultry alcohol produce. Confiscated one small steak and warned us about the other stuff. The guards were pleasant, we were at the border about 15 minutes. Other rv's drove by us. This was something new, an agriculture inspection. Not a big deal. We got stopped by the Mexican marines outside of Puerto Penasco, Briefly, stuck their head in the door , then waived us through.
We found that we really don't need to bring food items and stuff. We can get what we need in PP. They got a "WalMart" and Sam's Club just opened last year. Reasonable prices.
So not saying you will get stopped, just what could be on a random check.
This was our 2nd time being stopped in 10 years of travel to PP.