Part marking on a Aerospace pump rotor

[ph63915]

I am looking at replacing a nitrided steel pump rotor and it has an interesting couple of laser etched pieces of text upon it.
One is an M inside a circle which I believe means it is part of a batch of parts that have been subject to Magnetic Particle inspection although if someone could confirm this I'd be grateful.
The other is a capital H, I assume this is indicative of another inspection process but I cant find any reference to it.
Your assistance would be much appreciated.

 

[zeusfaber]

The M inside a circle could be a manufacturer's identifier (I think Capewell mark - or at least used to mark - their products with something that matches this description).

A.