Yes, this is possible using
find with the arguments
-group. For example,
find /path/to/your/directory/* -user uname -group gname lists all files (folders are also just files) in the specified directory, that have the specified user and group ownership. You might also want to use the argument
-type to limit your results to only certain file types, see
man find for list of known types if you are in need.
However, if you just want to make sure that all files and folders have the correct ownership, an easier solution could be to just overwrite all existing permissions, whatever they might be, using
chown without checking the old permissions first, but it depends on your use case if this is tolerable. For example, you could just
cd into your directory of choice, and traverse this and all subdirectories using
chwon -R uname:gname. Granted you have the permissions, every file (read: all files and folders) will have the specified user and group ownership afterwards.