I see the you have me with a Netgear modem, but I have a newer one and can not find how to update you.. Also, Netgear says I can not update filmware - only through you can that be done. I find on your site this gem: "...Generally, you can check for these (filmware) updates through your router's ...site ....". I'd feel slightly better with an updated modem-thing. Thanks.
All modem and combination modem/router gateway devices receive a firmware update when they connect to the system if they are not already using the most current version. Sometimes they have to be power cycled a time or two before the update is applied.
The line you quoted about router updates refers to standalone routers. Those don't include a modem component so Comcast can't update them, customers have to do it themselves.