I have seen this happening too many times and want to warn you that IMDB is not correct 100% of the time about the OAR of the movie. One example is Revenge (1990) listed as 2:35:1. Yet when you see the movie, you can clearly see the movie has an OAR of 1:85:1. I have seen others as well.
IMDB was developed as a user-contributing database and contains many, many errors of all kinds, including aspect ratio. Unfortunately, i don't think there is any single definitive source for determining OAR, at least one that is easily accessible to us rank and file.
