Nice project! Great that more WW1 planes are coming. Besides that, we have 100th Anniversary of the outbreak of WW1 in a couple of days.
As for the upper Lewis gun, this was a kind of option, used mostly on British-built S7's. Spad 7's were mainly armed with a single Vickers gun. Other options were Le Prieur rockets and sometimes she was carrying small bombs mounted on the gear struts. Judging from the screenshots, Vertigo will provide the British model (Brit gauges installed). On the other hand, it looks like an early model of the plane, powered by the 150HP Hispano-Suiza or one of the first batches with 180HP Hisso, because it is lacking radiator shutters on the front. One of the most important WW1 planes, no doubt about that, used from the Fall 1916 until the end of the war.
Good luck with the project!
Lucas