MR5200 Why aren't the firmwares on the Support website?

I have an "old" MR5200 that I would like to start using when I travel to replace the no wifi LM1200 I use for backup purposes.  The MR5200 is on NTGX55_12.03.09.00 and I believe that there are a couple of updates available since then.  My issue is my AT&T US sim works fine in my LM1200 but gives Broadband Disconnected in the MR5200.

I'll trek over to the AT&T store this week, but I would bet they ask me to update my MR5200 and it blows my mind that the firmware isn't on the site.  Meanwhile the LM1200 *does* have firmware available online.