Though there are numerous codes Truss Manufactures must adhere to, there are some important requirements as The Architect, Engineer and/or Purchaser can require, which will help insure you are getting Trusses which are built to code and for the Structure in question.
1. Require The Truss Placement Plan to be sealed by the same engineer that is sealing the Truss Engineering.
While most codes and/or Building Departments do not require the Truss Placement Plan to be sealed, it should. The reason is that you want to Truss Company and Truss Engineer to insure The Trusses are properly designed for the Placement and conditions per the Provided Architectural and/or Structural Plans.
Most codes and/or Building Departments only require an Engineer, which can be any engineer and not an independent 3rd Party Grading Agency to inspect the Truss Manufacture Monthly. This is not a good practice for various reasons. Most Engineers do not know lumber and how to grade it, nor are they licensed to do this and therefore cannot accurately inspect if the plate placement with the lumber are correct. Also knowing that a 3rd Party Inspection Agency is doing said inspections keeps everyone honest.