Airbox intake housing

I finally got my hands on this missing item. A bit pricey but I decided to do it for motivational purposes. The rubber hose can be obtained easily as they are reproduced. I thought it would be an easy job but I was wrong. I did not had it sanded and sprayed as I first wanted to have it checked. I ended up removing the rear wheel, the mudguard but that was still not sufficient. So I ended up unscrewing the middle section as well. Only to find out it did not fit. I was baffled, is this items different somehow. It's an airbox housing from a series 2 but I was expecting it would fit a series 1 as well. I need to have this further checked but I'm very unhappy about this