Is yours one of this generation? If so, you can learn to service it if you study Chris Sherlock's video tutorials, yes. But for someone who hasn't had prior experience tearing down and servicing a camera like this, expect to take a week or more to do the job. Whether its worth it or not is up to you. Do you want a project like this on your plate? Is the lens in good enough condition to warrant the effort? Will you actually use the camera when its done?
This generation of Retina IIa is early in the design process, and its not the best engineering. Kodak AG was still learning how to make a beamsplitter rangefinder, and this one's not the best. (they're not easy to calibrate, now that they're 70 years old). I would say that it depends which lens yours has. If its the 47mm Ektar, then definitely, get it fixed up. The f2.0 Schneider Xenon version is also worth fixing. But if yours has the f3.5 "Ektar" like whats on the camera in the photo, I would think twice about investing in getting the camera serviced.