I am working on a 1977 Dragon from InterFlip and noted that the far left/right standups weren't advancing the bonus.
Then I checked the schematics, saw that there was no bonus advance logic in the schematics for them.
Then I checked IPDB: all other photos of Dragon just have "5000 points" on the far standups, not "5000 points & ADVANCE".
On IPDB, the photo of the sales flyer shows "5000 points & ADVANCE". It is also mentioned in the advertised features list.
Does anyone else have one like this? Is it a prototype? An early version where they decided to drop that logic, but hadn't yet updated the playfields?