I found the 3mm more stood out more than the alarm position. {without checking state requirements etc...} Isn't 2mm body std across the board. If any State were to require an upgrade to 3mm there needs to be a lot of jumping up and down and requiring proof of instances where the 1mm difference would have prevented a theft. Any pen pusher deciding an upgrade is required needs to cough up some evidence or funds to support it.
I think my gun safe is 2mm body, 4mm door, although I have a 3/6 which was Cat C/D I think, that's used for tools in the shed rather than guns in the house. Seven years and counting, still waiting for that first inspection, probably couldn't get past the always closed gate and dog for a surprise inspection.