Questions about Firefly

Lert: The in-game Firefly:     VS the Firefly I'm most familiar with from pictures:     Now, the one in the photograph has a very different hull from the one in the game. In fact, if you look at the in-game one, it looks like they took a welded plate hull and welded the front-end of a cast hull on it. You can see the diagonal weld line starting above and behind the drive sprocket, above the first bogey.   Now, my questions are:   - Is that what actually happened with the Firefly WG scanned for the in-game model? I'd be very interested in learning the history behind that particular firefly. - I was under the impression that all (at least most) Fireflies had the hull as depicted in the photograph; welded plate hull with protrustions for the driver and co-driver. Were different hulls used for the Firefly? - If so, what hulls? was it just a specific series of Shermans that were converted to Firefly, or was it just a thrown together collection of whatever Shermans they could get their hands on? - Why does the in-game Firefly have an american M2 HMG on top? Shouldn't it be a british .303 or something instead?