Question about 4wd spring hangers for those that have converted from 2wd

[1972K20]

Hey guys, is there any difference in size/strength in the front spring hangers for the different series trucks? Also, will front spring hangers from 73-87 work on 67-72 trucks?

The reason I ask is LMC (yes, I know LMC's reputation) sells these, and I have a 1970 C30 I'm planning on a 4x4 conversion. My fear is that hangers from the 1/2 or 3/4 tons may not be as strong as what may have come on K30s in the later years.

Here are some links:

http://www.lmctruck.com/icatalog/cc/full.aspx?Page=160

http://www.lmctruck.com/icatalog/cc/full.aspx?Page=47