Does this pump you bought have a code number printed on the pump body ?
There are a lot of fakes out there , the price worries me but if it's genuine then that's a smokin deal. I would DEFINITLEY upgrade to the hotwire kit before you have a problem

Here's a pic of mine

 

my truck is still at the body shop, and we got 8 in of snow last week so I won't be driving it any time. soon. my pinion angle vibration is showing knock on the scanner if I punch it from a roll, I have 18° of timing in it but haven't seen that on the scanner.

once I get it back I'll take some measurements and get some shims ordered

I'll check once I get the truck back, I forgot to put my sock on anyways

I don't think it's a fake, maybe just a blem. most ebay stuff is so cheap because they have to be so competitive on there. they would rather sell more volume at a lower price.