46 Pickup Upper Support Arm Pivot Questions

I am getting ready to redo my front suspension. In the group parts book, the support arms assembly identifies a LH (BZ 164717) & RH (BX 164716) part. When looking at the pivot portion, I can see no difference between them.

Further, in the 40-42 parts book, I see that in 42, they switched to a 2nd type of support arm, LH (BX 164717) & RH (BX 164716), identified by nearly the same part numbers, minus in 46 - 47, one is prefixed with a BZ.

So a few questions:

  1. Does the 2nd type in 42 only refer to the arm portion of the assembly listed?
  2. Are the pivots that bolt to the frame the same between LH & RH?
  3. Is the pivot portion identical between 40-47 vehicles?

For reference, this looks like the part I am talking about:

Thank you for any help on this,