Multi part question here concerning F4U s upon carrier decks

1. When was the 3 bladed propellor F4U introduced to carrier decks during the war?

2. Who flew the aircraft ? USN aviators or Marine aviators and if Marine aviators were there “Marines” insignia upon their aircraft as we see after war?

3. When was the 4 bladed propellor F4U introduced upon WW2 carrier decks?

Any help will be greatly appreciated.