Oh, yes you should bother
The rust comes off with fine steel wool and some polishes are much better than others. Even if flaking chrome never will shine up again, the steel under does with the right polish. I like Pol Metal polish, Quick-Glo (probably a favorite for this). Autosol is acceptable too. They are thicker pastes, and better than the Brasso and Mr Muscle products I have tried (they work well for silver and brass though). This is of course on only for metal parts like chrome plates, needle and presser, bar, outer part of the hand wheel etc.
I usually clean the black shellac with microfiber cloths, and shine up with Auto Glym super resin polish. If there's still a good layer of shellac over the decals it works very well. Gold decals are the most delicate on the machine and easily get's damage if harshly cleaned.
Is the shuttle still with the machine? Helen Howes shop is the place to call for replacement parts. The advantages with model 28 is that needle and replacement long bobbins can be found. At least two people I know of have said their 28 is their best top stitcher, neatest precision stitching. Yet a couple of others have set it up with a buttonholer.
For the mechanical internals, oil, fine steel wool, metal polish, loads of cotton buds and wipe excess oil off, and repeat for the next few weeks. There's good info on the 28 if you like reading blogs and watch
youtube videos.