Yes, for a 10.00-11.49 roll bar you only need the side bar (door bar) on the driver's side. In my 28 years of racing (crap, am I that old?) I think I've only seen 2 or 3 cars with the side bar only on the driver's side.
One interesting point of interpretation of the rules is whether or not that side bar can be bent at all. When I built the rollbar in my street/strip Vega, the division tech director told me that it could NOT be bent, as the diagram in the rulebook shows it straight. I'll bet in the last few years I have seen at least 100 cars with bent sidebars (where it bends outward to run right against the door when it is closed), which gives the driver a lot more room, but at the expense of some cage rigidity. Then again, since they allow swing-out sidebars, why not bent ones? I asked our current division tech director a couple of years ago, and he said a bend is fine as long as it otherwise meets the defined requirements.
Regards,
Michael Pliska