Great job!, it looks perfect. The treadle irons looks like they are in very nice condition too.
The knob is notorious for needing exasperating repetitions of oiling, ...daily, for weeks on end in the worst of cases. You machine probably is probably on the easy side. It looks like it's in very nice condition, no excess oil or grime mess. There are tutorials for taking off the knob, as well as the cam stack, but unless there's rust or lots of dried up grease, regular oiling should do the job.
Best of luck