Keep in mind that the missiles will be homing or guided missiles. The sights for the gun part of the system don’t really matter as the missiles really only need to be pointed in the general direction of the target and launched. The mount they’re on will have only minimal involvement beyond launch.
FYI, the Russians have been very successful with recent gun/missile combo systems. The Russian Tunguska (SA-19 Grison) self-propelled AA gun/missile system has a pretty good combat record.
The Tunguska may had a decent record, but the naval Kashtan system, which uses the same SAM as the former, seems to have been a disappointment. It has a higher minimum engagement zone (around 1.5 km) for antiship missiles and low warhead weight. The Russians have never standardised on it, while India and China have installed it only on a few ships built in Russia.