Technically VF-42 was not at Midway. The squadron HQ, the CO, LCDR Charlie Fenton, and XO, LT Vince McCormack, was at MCAS Ewa on Oahu. The remaining pilots of VF-42, 16, I believe without looking it up, led by LTJG Bill Leonard, had trooped over to NAS Kaneohe and were TAD to VF-3 under LCDR Jimmie Thach and actually made up the majority of that squadron's flyers.
So, the planes flown by VF-42 pilots at Midway were all marked as VF-3. As noted above, photos can be found here,
Battle of Midway but you have to work your way through, there's only 15 pages .. . page 5 has a nice shot of my father's VF-3 F4F taking off from Yorktown (or you can look directly here
80-G-312016 Battle of Midway, June 1942).
VF-3 F4Fs were all plain-jane F4Fs with the squadron insignia on the access panel just forward and below the cockpit, both sides. White numbers in the usual places, nothing unusual.