How many PCBs? The reason I ask is because its all subject to economies of scale . . .
I would say its not worth it, but it really depends on the quality of circuit you require.
Solder masking: "The main purpose of masking is to prevent solder bridging of pads and traces during mass production. There is also an esthetic value to consider. When using surface mount devices it is often necessary to provide a solder mask layer for both the Top and Bottom of the board as there will be differences in pad locations between sides where SMT devices have been added."
If you design your board well, or you arent doing that many boards and can test each pin for accidental connections, you wont need masking.
I dont know much about silk screening, but I think it is good for protecting really thin traces during the etching process. Someone correct me if Im wrong. Probably not needed if your traces are thick.