OK. I got out my old manual before spouting off. The new hub you have does already have the bearing race installed. That is why the bearing fits when you put it down in there. You can start a whole 'nother argument about whether you should pull this race out and replace it with your new one.
Now I don't really mean PULL the race out of there. What you would have to do is turn the hub over and locate the knock-out spaces that allow you to DRIVE the race out of the hub with a punch. The race fits VERY snuggly in there and it takes a good bit of hammering to drive it out with a punch. A race will NOT just drop in place as the one did when you put it in on top of the pressed in race.
After reading your posts and using them as a gauge, I would advise that you just leave this race in place and use it. After all, it IS a new race and races are not hand-fitted. They are plucked out of a tub of like races and packaged. Any one should work just fine. This will take one oderous task off your shoulders!
If you don't already have one, I suggest that you buy or even borrow a Haynes manual for these year trucks. It is a cheap investment that will save you loads thru the years. I looked up the schematic in mine before I posted this. I tried to scan it, but the quality was terrible. I have both the Haynes and the Chilton manuals as I have had a LOT of these trucks over the years.
I wish you weren't so far away, I'd drop by and TRY to help.