Not really. 201 stainless steel is a pure austenitic material that uses the manganese to promote the austenitic structure. In other words, it contains no ferrite. The 304 stainless contains a small amount of ferrite, usually around 4-6% ferrite, and the ferrite aids in counteracting solidification cracking. In your situation, you can probably use the 308 filler metal with no problems when welding these materials to each other. If you wish, you can go to a 309L filler metal if the application is more critical.