There are no code requirements for MT of Normal Fluid Service or Cat. D welds. MT only comes into play for severe cyclic and in that case for socket type welds that are not RT'd. That said, the drawing in your case rules and your acceptance criteria should be: 344.3 Magnetic Particle Examination Examination of castings is covered in para. 302.3.3.
Magnetic particle examination of welds and of components other than castings shall be performed in accordance with BPV Code, Section V, Article 7. Note too that acceptance criteria can also be made more restrictive by the fabricator or purchaser.