Lee, the 1952-53 Kaiser Parts List Supplement lists totally different numbers for the front and rear bumpers used on 1953 Manhattans. The change reflects different holes on the bumper for the bridges and other features. While the 1951 KAISER SPECIAL OR DELUXE bumpers will mount on the car correctly, it won't look right in the front and as Jim points out, does not work at all in the rear because of the tail lights on the 1952-53 models.
Why do you want to switch out? Also do you have the shop manual (1951), shop manual supplement for 1952-53 models, parts book from 1951 and the supplement for 1952-53. You will need them if you are restoring/maintaining a 1953.