I have installed a few hundred in the last 2-3 years alone.
Yukon has TWO lines! Premium and Value. Premium are good, value are same foundry as the likes of genuine and other asian imported sets. Premium's come from the foundry's located more so in Itialy, mexico, MAYBE USA but thats old stock if so, etc, and those are the SAME foundry's that supply gears to Precision, Yukon, superior, Alloy, etc....
THe big picture is on gears.. Are the gears in the box concidered a Entry level el cheapo variety or the premium Quality and steel? Almost Every name on the box "resellers" of gears off the two lines. Some companies have one division (Alloy say) that boxes only the good stuff, where thier other sister company is hit and miss (precision).
Now your Question...
see if there is a country of orgin marked on the box or gear set. if you can comtact the company that sold them to you,and IF they are Honest, see if they will tell you which version o the yukon's you were sent. If they were more then 120$ total per set then you got ripped off either way. A permium Yukon set for most any axle can be had with shipping for under 149 and most for te Jeep axles for 129.