Bank 1 on your truck is the cylinder bank closest to the firewall. The bank 1 air fuel ratio sensor is located in the bank 1 exhaust manifold. The bank 1 sensor 2 oxygen sensor is located in the exhaust pipe from that bank, close to and downstream of the converter.
Sorry to argue about a dealership's diagnosis; but they should have told you that the code for a converter being bad comes from the computer comparing the readings from the two oxygen sensors; and because of that, it is not possible to determine whether the code is caused by bad oxygen sensors or a bad converter without first replacing the sensors and clearing the computer code with a code scanner; and then seeing whether the code comes back. The "shotgun approach" they gave you of changing all the possible parts at once covers their behinds, at your cost for buying expensive parts which probably are not all needed. You'll need access to a code scanner to clear the codes. This valuable tool can be purchased from parts stores for about $50.
A 7/8 inch oxygen sensor socket is a useful tool for installing and removing the sensors; as it is made with a slot in the side for the wire to fit through. But a crescent wrench can sometimes work in a pinch. However; I've been told that the access to these sensors on this model is rather difficult.
I recommend buying the sensors from www.rockauto.com After you compare their prices to the dealer's prices for the same identical parts; you'll see why. If you end up buying a converter; check Rock Auto and also check Auto Parts Warehouse.