93 Wheel Hubs?
 

I have a question?
A friend who owns a 93 3/4 ton 4X4, needs new front wheel hubs.
Dana 60, casting number 102784.
The problem is the parts now are now considered obsolete.
At least that is what the dealers say.
I have found some rebuildable hubs, but, the casting numbers are different.
They are 99756 and 100353.
One dealer said that the numbers must match!
What is the difference in these hubs?
Any help will help.
Best would be if someone knows where I can find matching hubs, new or used as long as they are rebuildable.
Thanks in advance guys.