that washer doesn't look bad at all!
i have 6 of these machines, one i even dropped off a truck and had to peice back together!
3 of mine work fine right now, 2 more are almost back together and one i picked up last year that has considerable rust in the tub. the tub on yours looks great!
these washers seem easy to work on to me and are remarkably durable. i clean rollers with alcohol and very lite sanding, i do oil the agitate arm, and the tub seals seem to hold up well. never had one leak yet. that outer tub is so big in relation to the inner solid tub that when it spins out water the level doesn't even reach the tub seal under normal conditions.
i did download the service manual for the 65 models from here, as well as the later 68 model. it was helpful.
will look for that cap this week.