Lawrence,
While Flynn is credited with some design changes, I haven't found anyone or anything that can detail what that might have been. We do know that Flynn's construction company, Toomey and Flynn Contracting Engineers, built the course according to Alison's plans. A few years before Alison proposed going into partnership with Flynn. We're not sure if it was a design partnership or design (Alison) and build (Flynn) partnership. I suspect it was design because Flynn was apparently offered the partnership and not Toomey and Flynn.
Whatever redesigns Flynn may have made are less apparent today. The greenside bunkering and fairway bunkering has been redone by Arthur Hills as I recall and is rather systematic in look and placement. A 1937 aerial looks a lot different than it does today. There were very few bunkers on the course, perhaps AW Tillinghast was hard at work there or the club decided they had to reduce maintenance costs. The bunkers that are seen in the photo are not typical of Flynn bunkers. Perhaps Flynn's work, if any, was done while he was doing work in the area on other courses a few years later shortly before he died.