Cable modem/router and NAT

I have a simple cable modem (Thomson twg870).

1. As i've seeked the manual there is no such an option to select the NAT type the router use. Can i conclude that the only and default mode is port-base?
2. The LAN computers have by default access the inteet (that is just after coecting the LAN stations; without any configuration in the router panel). Does it means that the NAT functionallity is enabled by default?