June, here is a little bit of information on them in this page. I don't know how rare they are. http://web.ncf.ca/cn333/esbfigs.htm
The page indicates that these were sears Canada packs so I am unsure if they were also released in the US. This was the pack from sears Canada that came with the skinwrapped figures on generic cardbacks so seeing as the pictured one doesn't have one of those, but rather has the exclusive lobot on a regular card it is possible the set is either a mixed set or that these were also issued in the US with standard cardbacks.
I have caviar dreams and McDonald's pockets