Front leaf spring U-bolt clamps interchangeable on '71 Blazer?

[Joe Blaze]

I just got a set of Tuff Country 2" lift springs put on my '71 Blazer and i think my guy may have swapped around the heavy clamps that hold the U-bolts onto the leafs and axle. Can anyone advise if they are interchangeable from left side to right, and does it matter what direction they go on? I notice they have different part numbers on each one, but they look the same to me. Here is how he put them on:


The driver's side as seen from wheelwell:





The passenger side as seen from wheelwell:




Also, the LMC catalog shows a spacer under the clamps, is it necessary? i don't have any on mine.