I know later on they were in 1As, but I've seen a photo somewhere around here of Boyington in a -1.
Thing is, the F4U-1 and -1A are a bit tricky to differentiate because there was a pretty steady ongoing series of improvements in the -1, From what I've read, the USN/MC didn't originally note a difference in designation until LATER in the run. At either a certain BuNo or S/N I think they established that all prior Corsairs built with the bubble style canopy were -1As.
These are HYPOTHETICAL numbers, though I'm sure WW and DOA can come back with the ACTUAL ones, but let's say F4U-1 #1056 was the first produced with a bubble canopy. At this point, they were still designated as F4U-1s. However, at #1265 they decided that there were enough significant and common improvements being shared by ALL Corsairs beginning with #1056 to make for a seperate model, so they redesignated all those Corsairs ALREADY built and those still under construction as 1As. So basically, they back-dated the F4U-1A to #1056, even though they didn't actually come up with the differentiation until #1265.
Once again tho, that's what I've read about it. I'd wait for WW or DOA to have their go at it before accepting it as fact.
It gets a little more fun because as has been posted 'round here before, the F4U-1Cs weren't manufactured convenient block like the 1A and 1D. The 1Cs were drawn pretty much at random from under-construction 1A fuselages with reworked wings to mount the 20mm, so the S/Ns or BuNo for the 1Cs are sprinkled in with the 1A run.