I don't know if you refer to the biggest of the two fonts around the circle (which I think is Engravers) or to the font of the letters "OC", which I couldn't identify.

Thy with this font. (bolded)

I think the font you're looking for is DIN.

I think it's this one.

The first font.

I think this is the font you're looking for. Hope it helps!

Sorry, I have just realised the "R" in the font I suggested in my last message is different to the one in your picture. Try this font instead.

I guess it's ITC Stone Informal. Hope it helps!

I have been looking harder and I have finally found the font, it's called Candice. Thanks anyway.

The font is Goudy Old Style with small caps. If you use Windows you surely have it 'cos it comes with the operative system. Hope it helps you!