It's standard practice and highly recommended to replace spring/axle U-bolts and hardware whenever they are removed, for safety's sake they are not considered reusable.
http://www.eatonsprings.com/atqReinstallingUBolts.html

Any spring shop can make them for you if you take an old one in or have good measurements, they are not expensive.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-