You guys are very close to the right answer. The gunsight is a San Giorgio Tipo C. The aircraft is a Fiat G.55 Centauro. It was one of the best Italian fighter aircraft of World War II. It was designed by the Italian engineer Giuseppe Gabrielli and first flew in 1942. Many historians consider it the most capable Italian fighter produced during the war.
German pilots who tested the G.55 during WWII rated it excellent against Allied aircraft like the:
Supermarine Spitfire
North American P‑51 Mustang
Fiat G.55 Centauro generally used an Italian San Giorgio reflector gunsight, commonly referred to as the San Giorgio Tipo C (TIO-C) or similar variants.
However, in some cases German gunsights like the Revi C/12D gunsight were also installed when German equipment was available or during cooperation with the Luftwaffe.
It also has a lot of colorful paint schemes. I should be ready in 2-3 moths.
