As much as I respect LTG's expertise, I don't take ANYONE's advice as gospel, especially when they are using a word like "seem". I try to think through the entire problem, weighing everyone's advice and trying to make the best decision about how to go about solving it. Most of the time, this does fall in line with LTG's recommendations.
The Williams part number is 02-3905, the Stern part number is 530-5004-00.
So, I started looking up posts, and Pinball Life has one to choose from:
http://www.pinballlife.com/index.php?p=product&id=324
It doesn't say whether it's for Williams or Stern machines, but it uses the Stern part number.
BAA fails when searching for the Williams part number, but has this one for Stern:
http://bayareaamusements.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=MP-530-5004-00
Marco brings up two matches for the Williams part number, but when reading the details, it uses the part numbers as if they're interchangeable, and says 530-5004-00 replaces 02-3905. Both are out of stock, BTW.
I haven't called PBR yet.
So, I'm wondering what the difference between the two could be. The only things I can think of are different metal or a different mechanical design. How can I know if what I'm getting has the Williams magic or if it's just a re-badged Stern post?