I just took the test this weekend, on Saturday actually. It took me about 4 hours, and I did take time to look up answers. I was very familiar with my materials, and I knew where everything was in my binder, everything was labeled, etc. If I hadn't been that organized I think it would have taken me longer. I don't have my results yet, it takes 5-10 days.
I actually emailed the AAPC specifically to ask if that list of references was considered the 'study guide' or not. The email I got back said that no, it was not, and that it was fine to print off anything on that list and take it in to the test. The only thing I couldn't have was the 'official' study guide (which doesn't exist yet) and the HCCA manual (which I don't have and never looked at).
When I got my pre-exam confirmation email from my exam proctor, I emailed her and asked if she had proctored the CPCO exam before, and asked if she had any questions about what materials were ok to bring in. I didn't want to show up on test day and have an issue. My proctor was not familiar with the CPCO, this was her first time proctoring it, so at her request I forwarded the email I had received from AAPC saying that my materials were ok. My proctor did a little research, and all was well.
Amy