They are not unusual and there are many both graded and ungraded examples, I think I have two or three with varying amounts of roller marks. The mints have a fairly broad range of what is considered ok in terms of quality control, just consider all the 1955/1955 double die coins that got coins and released. Or the 1922 "plain" cents that were created due to the excessive die wear of the Denver die, and that is just two examples of one series where is QC had to be tighter those coins would not exist in the quantities they do. As far as grading its mint made so really it should not affect the technical grading, however it falls under the eye appeal side of the current market grading so its more of a case by case evaluation. The same is true for buying and selling, it clearly bothers the op enough to pass on buying, for myself it does not really bother me but I would not pay a PQ price for one with roller marks.