Is this a cleanout?

I have no visible cleanouts, but I found this old pic of the drain stack from when we were finishing the basement. Is that stub off the PVC with the red arrow pointing towards it possibly a cleanout? If so, I'm thinking to just cut a hole in the drywall there and replace it with a plastic cover for future access. Judges?Attachment 50518 (http://www.doityourself.com/forum/attachments/plumbing-piping/50518-cleanout-cleanout-maybe.jpg)