Yes, I think you need to replace them, you should use 1/4" fuel line hose from an autoparts store, I got mine at Carquest, about $2.00', you will need about 20' (25' if you replace the vent lines), and about 20' stainless steel clamps.
The gray fuel lines deterioate with age, they produce a green goo which will go everywhere in the fuel delivery system. You need not only to replace the fuel lines but you also need to clean and\or replace the main fuel filter, the carb. filters (these are usually really bad), and replace the fuel selector valve.
Replacing the vent hose is optional, I didn't need to replace mine, the vent is not part of the fuel delivery system.
Lou
