Yes, Onappaffa is the group which helps people get the temporary styrofoam 'farm' plates. The first step in the permanent legalization process that eliminates people from having to go to the border for same.
Now, Onappaffa is waiting for the green light from the government so Onappaffa can assist the 'temporaries' in completing the process whereby, voila, their vehicles are nationalized with permanent Mexican plates and they can drive them anywhere in Mexico. And, again, no border visit.
They think this will happen in June, but perhaps sooner. The powers that be have a say in when and where and how many legalizations can take place.
So, for now, only the temporary plates are being issued while you wait for the next step.
Is this clear as mud? Let me know, , Cruz