I agree with Trigen. My opinion on research is that it's a yes or no issue; either you have some research or you don't. Most programs will look at your application and if you have one or two publications or projects, then you are good. The obvious exceptions are major research oriented programs, but even there I would doubt it would be a make or break issue with your scores.
It's not too late to get on a clinical paper during your third year. Third year grades are your top priority, but you can always bang out a paper in a few months. Get in touch with the RESIDENTS in your program, and tell them you are interested in helping out with a paper. They are the guys who will know what is going on and, at least at my med school, they were always looking for some help in getting stuff out. I'm not sure where you are, but you'd be surprised at how many projects are going on at one time at any given program. So if you can get on a project or two in your last two years, then you have that box filled on your application. It's really binary in my opinion.
So I think with your Step 1 score and grades, and probable AOA with what you said your possible class rank was, you'll be a strong applicant on paper. If you get even one paper out you should be even better. That said, a year of research won't hurt you in any way other than an extra year in training. But I doubt it's necessary. The other thing with taking a year off is that lab research is notoriously tough. Things take a lot longer than you'd think, and you could easily spend a year in a lab with little to show if you don't pick your projects well.
Also, I think doing well on away rotations at a few programs in California will obviously help. If you are strong on your aways, get along with the residents, show them you're a normal guy who works really hard, then your chances are great.
Let me know if you have any specific questions. Ortho is a tough match, but don't get scared by all the things you read on this board. I'd say very few people who match have a dedicated year of research, even with lesser scores.