Michael - I have been looking at a lot of images of A-1s, and I am not seeing shutters. Just an open cowl and the crankcase cover.
As in this photo (
https://www.pinterest.com/pin/316166836328684905).
Do you have an image of these shutters, Ray?
Incidentally, as far as I know, all the USAF and VNAF A-1s were ex-Navy birds.
Don