Looking into the whole Hurricane armor plate thing, it appears that at least one Hurricane MkX (Canadian built Mk IIb with U.S.-made Packard Merlin engine) with 12 guns, was supplied to the USSR with armor glass. The mounting is visible here, although the armor glass is missing:
http://www.jneaircraft.com/am274/artifacts/
This particular plane has a fascinating history and models several Hurricane variants not available in IL2.
First, it was a Hurricane MkIIa originally fitted with 12 0.303 caliber guns.
Second, once the Soviets got it, they removed the British guns and replaced them with 2 ShVAK-20 mm cannons and two-UBT-12.7 mm MG in the wings, with ejection ports for the 0.303 guns faired over and new ejection ports and chutes fitted for the new guns.
Further pictures show that it was fitted with Soviet wooden propellor blades.
http://www.jneaircraft.com/am274/history/
As you scroll through this web site, you'll notice several places where bullets punched through armor - one through the rear bulkhead to wound the pilot, another where a bullet missed the pilot and the reserve fuel tank bulkheads and then punched through the firewall (missing the armor plate) to hit the engine.
Since the plane that shot down AM274 was probably a Fw-190A armed with MG 17 (7.62 mm) and 20mm cannons, it's proof that rifle caliber bullets could sometimes punch through armor plate if fired at sufficiently close distance - and if they were AP rounds. So, the armor on the Hurricane series didn't make it invincible, but it helped.
