Here is how I think it will work James but we are gonna call Mexico City Immigration, we don’t ever talk to the locals here, and confirm this.
If you have a current FM2 or FM3 visa then you can go to a Mexican consulate in the U.S.A. and do the paper work. Then on your return trip to Guaymas you will take that paperwork to Immigration here in Guaymas and finish it off and get your new Immigration Card with your picture on it.
Again we are going to call our Mexico City contact at immigration and double check that information for you.