1970 rear control arm question

[jasonmiddlebrooks]

So I dropped the rear end out of my 70 c10 to clean it up, replace bushings, shocks, coil springs, paint, etc. I noticed one of the rear control arms have a piece wielded on the top and bottom. Is this something that they would do at the factory? My Dad bought this truck new in 70 and has been the only owner. He wrecked it right after he bought it new but does not remember anything done to the rear end (but that is not to say something was done). Here are some pictures. Thanks.