As stated before, best to check with your locality.
Out here in California, any food that is prepared for service to the public (with specific exceptions now) must be prepared in either a commercial kitchen or restaurant kitchen. If it is not a certified commercial kitchen then the food must be served on premises. So, the answer here would be yes, it must all be prepped in your commercial kitchen, and anything that is served cold, cooked or not, must be prepared and packaged in said kitchen. While food trucks can be certified as commercial kitchens, you still have to work out of a commissary for things such as cold storage, foods sold pre-packaged and food handling outside of service.
The SS Platypus, sails again, to the support of the Vets!
"perhaps...but then again...maybe not..."