The MkII rule book clears that up. Thankfully that’s how I’ve always pronounced it! The Brew City Gamers (see video below) posted a nice overview of the book for anyone who doesn’t have it yet.
On a side note – I’m going to stop talking about MkII now. As of this month Warmachine is MkII. If I need to talk about the past (and why would I) I’ll explicitly mention MkI.