Hello,
The highlighted number in the product code denotes modem module used within the router, which, as you have assumed, relates to certifications and permissions to use router's within certain networks.
Devices with RUT240 *1**** have a module certified to operate in AT&T, Bell, T-Mobile networks.
Devices with RUT240 *2**** are certified for use in the Verizon network.
Best regards,
