Merlin,
This is an AHJ call, in my neck of the woods you only need 3 conductors L1-L2-N as long as the load center is a "reasonable distance" from the meter. When I pressed him (the AHJ) on the distance he said less than 15 feet. Anything over 15 feet requires a main disconnect on the outside of the building and 4 conductors L1-L2-N-G to the load center. All these conductors must be insulated, even the EGC. The reason he gave me was to limit the length of unfused/unbreakered service conductors inside the building. So to answer the question 3 wires and a bonded neutral in the meter, and load center would be fine here.
