Is this a Metro XFi motor?
 

I saw a potential donor for a high mileage car I'm building (long story, but the short form is, two seat mid-engine removable roof), it's an xfi <but> there was talk of the previous owner putting in a "new engine". I made a temple rubbing of the engine serial number, it is:

G10N903938

So...is this an ordinary Metro motor or the Real Thing? Is there any way to tell without tearing it down and counting piston rings?