I really don't trust Rock Auto after they listed the VX front bumper reinforcement (with pictures) for like $50 when Isuzu wanted $350. I ordered one anyway just to see, and sure enough it was complete bunk. They ended up sending me some flimsy piece of metal that actually belonged to a Rodeo. NOT cool.
When I was doing my front axle stuff I actually ordered all of the parts to do a complete axle swap (axle seals, axle bearings, steering knuckle bearings, wheel seals, etc., etc.) from Scarff Isuzu: https://www.partswebsite.com/isuzuparts/ They are great and ship out quickly (if they have it in stock).
You're looking for #3 on this diagram: https://www.partswebsite.com/isuzupa...60&catid=10016, but you should probably replace the axle bearings (#2) while you're in there. They are fairly cheap ($18 each, you'll need two) and since you're going that far in to replace the seals, replacing the bearings at the same time will just be cheap insurance.
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong, it usually turns out to be impossible to get at or repair."
-Douglas Adams, Mostly Harmless