Maybe I step into a legit WW2 USN patch soon, so I can put an original on it to close the stitching holes.
Thx for that...I actually think this jacket is a candidate for a reproduction patch. A real WW2 USN patch is going to be expensive, and it will be hard to match the holes. A lot of WW2 USN patches were 4" not 5" or oddly shaped...meaning not round.
At the time these reproduction patches came out there were 100's of designs to pick from, both AAF and USN. They all were on the same roughly 5" leather blanks, with the same high level of artistic execution. One problem as far as originality, is many patch designs were never originally painted on leather. They might have been decals, embroidered, made with layered leather, painted on canvas, embossed, and on it goes.
For your purposes, I think you need a Navy patch to cover the holes. It is not like you have a jacket that had the patch removed and you know what went there. That is sometimes the case with A-2s where you have a name or pictures and know exactly the patch that went there. In that case, you really do need the perfectly correct original patch to make a proper restoration.
Getting back to your M-445A...they most typically did not have patches on them. When they do, they tend to be from transport and patrol/bombing squadrons...but I don't see why you couldn't pick anything...though if I were having something made, I would look at some of the designs from the ETO patrol squadrons that flew out of England....not something from the Pacific Theater. Patrol Squadrons flew B-24s and its Navy variants...and other multi engine planes like PBYs, where the crews wore M-445As. It would take some research to find out which of these squadrons wore patches...most did not...but that is getting maybe too picky.
Anyway, there is some fun to be had researching, but I would not suffer over worrying about finding an original patch for this restoration.