That should be all you need, combined with compressed air to blow the cleaner through the passageways. Those carbs don't look bad enough to need a soak. Spray some of your carb cleaner into a little cup and dip old toothbrushes and Q tips in it then scrub the parts clean. Carb cleaner is pretty strong stuff so I like to rinse it away afterwards with something milder like WD40 or kerosene. Blow it through the passageways to flush out any remnants of the carb cleaner. And be sure to keep the carb cleaner away from the rubber parts, it can destroy them, especially the slide diaphragms. They'll shrivel up like a used condom if you apply carb cleaner to them, lol.
Yes, that is stock jetting for that carb set, stock needle and clip setting too. I don't think the P.O. was doing much sustained high speed running down the interstate or he probably would have seized the motor, lol. The other thing you have going for you is that missing o-ring on the needle jets. That could have allowed more fuel through, flowing around the outside of the jet instead of just through it, so it could have been running richer than stock like that. That would sort of be like re-jetting.
If you plan to run the basic mods similar to what you've got now (pods and pipes) then yes, you better re-jet a little bit. Usual routine for your carb set is one up on the pilots (to a 27.5) and mains in the low 130s. I would get 130s and 132.5s to try out. With the larger mains, you will need to lean the needles one step (raise the clip to the #2 slot).
Reading around the site you may run across many running mains into the low 140s. That's entirely possible on some of the other carb sets that had stock mains in the 130s to begin with, but you'll never get that big on your carb set. Your small 122.5 stock mains and large Z-8 needle jet won't allow it.