1932 Ford Spring Perch ID

I thought I had a Pair but if you look closer they are different with the one on the right is made a little bit stronger with a thicker casting?? Any Ideas? thanks

 

I'm guessing the thinner one is original and the thicker is a repro. Does the thin one have numbers on it and the thick one none?

 

I would guess the heavy one is from a BB 1.5 ton truck. All the parts look like pss but much stronger.

 

I think shank diameters , the bolt part, would vary if one is BB...are they different there?
Look at uppers for prefix codes...B, BB, 40, Hecho in Argentina, etc...most around are 40's
You may just be picking up differences from difference forging tools and suppliers. Ford made its own forgings from proprietary steel formulas and heat treats, and had them made by forging suppliers like Moore as well. And of course there were multiple toolings, and even parts produced after 1934 production to keep the parts bins refilled.