I have been looking for a 57 for several years, or more like watching for one. It seems mostly I find 1960 models, then 59 second, 58 third and darn few 57s.
This also seems to hold true in my favorite junkyard. Out of 16 fridges, 9 are 1960, 5 are 1959, 2 are 58 and none are 57.