A 24mm name brand lens for $40 is always a good deal, especially if it really is in working condition
Probably the 200mm for $50 is a good deal as well.
However: you do realise that without the extensive surgery detailed above, the 'fit' is really not a secure, constant thing... I wouldn't wander around with a Nikkor on my Pentax. It might well fall off.
Also: the Nikkors have their own mythologies as to which are the good ones - but in no way compare them to the SMC Takumars or Pentaxes of the same era. This is a cute way to say: Nikon was late to the SMC game, so you'll likely get more flare. The overall performance - except maybe for the dogs and stars of the line ups - is probably about the same otherwise, in real life. One design may prioritize edge resolution or contrast, while another seeks to maximize the center as fast as possible... and so on.
Here's one guy's opinion on all things Nikkor...
Lens Evaluations
If you buy them, you ought to then get a Nikon FE or something similar that can use the non AI lenses natively. Then you can get the full Nikon film experience.