A 1952 would indeed make sense with that brake set. The fenders, grips, and shifter are add-ons from a later time. 1955 would be the latest bike I've seen with the Schwinn-built brake set, but I think you're onto something using the 52 serial number.
I've always been somewhat interested in the weird period of 1953-54 when you see oddball parts on some of the bikes - Brampton shifters and hubs, and the short-lived Birmingham style English brake sets.