Aztech HW550-3G

Overview
"250-323300-401" is silkscreened on the board in the FCC photos.

The default SSID is probably (it is the format shown in the manual) Aztech_XXXXXX where XXXXXX is the last six hex digits of the wireless interface MAC address.

Probable 00:30:0A (Aztech) OUI (on board MAC label in the FCC photos)

Links of Interest
Some part detail on the DD-WRT forums which is partially contradicted by the below On the OpenWrt forums