Roger!
This is a link to Wellnuts being sold on Ebay.
http://www.ebay.com/itm/25-Well-Nut...Parts_Accessories&hash=item1c345aac69&vxp=mtr
From what I see these are the ones we need. I have checked out my old ones and I can see the WELLNUT letters casted in the rubber. But I'm not sure about the threads!!