McGaughy's Drop Spindle Question

[NoNeck]

My son purchased a set of McGaughy's Classic Drop 2.5" Spindles from a forum member. We have the spindles installed, and the ball joints and tie rods bolt up just fine. His truck has an '84 front suspension cradle, so the drop spindles were supposedly for the '73-'87 trucks.

The numbers cast onto the face of the spindles are "6072L and 6072R". The original McGaughy's box states to use "Heavy Duty" brake components.

We have contacted both Summit and Jegs to order cross-drilled and slotted rotors for these spindles. The problem is, they don't show a part number for the spindles. Plus, when I do a Google search, nothing comes up.

I am wondering if the number "6072" might be a very early McGaughy's casting, and designates the model years '60-'72?

I guess I will try to call McGaughy's when they open. Any info until then would be appreciated.

Thanks, NoNeck