Both WM's where I live carry plenty of both PP & PU.
When I went to buy 2 jugs of PP last week, they had 4 jugs of 5W-20 PP on the shelf, 2 had intact neck rings and 2 did not. I bought the 2 with intact neck rings.
I hope SOPUS doesn't require receipts for the FRN discounts as I mailed my original receipt to them for the PP for the $10 rebate per jug. Everything I saw didn't indicate you also have to use the receipt for the FRN discount based on the Pennzoil web site, the $10 rebate sticker on the jug, and the FRN offer on the string around the jug neck.