If those are the rockers for a standard (stock) SB head, they sold for about $550 (the W2/W5 were about $750). I designed them and ran the very first set on my 340 Challenger with stock heads. With a flat tappet cam or hydraulic roller, they will run forever. They should be complete with shafts and spacers. If not, pass on them since you can't buy the special shafts anymore.

PS. Don't pull the rockers off the shafts if you don't have to. The early versions used roller bearings which were not caged and the needles will fall out. Reinstalling requires holding them in place with a little grease (assuming you didn't lose any when they fell out), and holding your tongue just right. I wanted to run caged bearings from the beginning but Erson had a ton of the other bearings they wanted to use up first.