Thanks, based on the statement below that I found on the internet the -3Ps make sense because the photo is titled "Flight Line, Kiangwan Field, Shanghai (China). These were part of a group of photos showing construction of Yonabaru Field (Naval Air Station) on Okinawa.
Similarly, a Marine photo squadron started training in March 1945, also reaching Okinawa by V-J Day. During the rest of 1945, production continued at a lower rate toward a planned total of 400 F7Fs, and Marine Tigercatsquadrons were cut back. Two squadrons operated in China -- Marine Photographic Squadron 254 on coast photo mapping with -3Ps, and VMF(N)-533 with -3Ns replacing -2Ns.