This question is in the context of a production environment where part numbers and change notices are strictly controlled, and any alternate manufacturer parts under an internal part number must be equivalent components.
For Class 2 Dielectrics, the rating codes are well defined. When requesting a new part number X5R and X7R are not equivalent are are given different internal part numbers (even if they are valid substitutes in a given design).
For Class 1 Dielectrics the picture to me is a little fuzzy. I recognize that there are a few different dielectric codes associated with Class 1 parts.However, C0G and NP0 specifically are used by some manufacturers interchangeably. Also, some distributor search engines (e.g. Digikey) will give option as NP0/C0G when filtering capacitors.
As an example there are two equivalent parts from TDK, an 0603 1000pF Capacitor. One is sold under NP0 designation the other under C0G, their spec sheets are identical...
My question is, when applying the most stringent view of production Change Control and Controlled Part Numbers, Could NP0 and C0G be considered equivalent or synonymous?