Pics would be a definate help. The early production model 29's featured cylinder and extractors that were recessed for the rims. However, I believe that the 629's date to a period after those recessed cylinders were eliminated. From what you seem to be describing it sounds as if you have a 629 that has an extractor star for an earlier model 29 in it. If so, it isn't correct, however I have no idea at all if this would be harmful or not.