I believe the picture shows that the struggle it had trying to produce a spark that could jump that larger gap.
The rotor has lots of black on it's contact, and perhaps might indicate the same thing on the underside of the cap. Can't see the rotor tip that well, but if it's crusted over with carbon buildup it needs to be cleaned. More likely replaced though, since it's of unknown age and not expensive.
And if I'm not mistaken, your distributor's points cam is trashed! It should be smooth with just the indication of the points fiber bit riding over it. Not grooved and pitted like it looks from here. Could just be the light and angle of the camera, but it looks worse than most.
If you are going to keep this style of trigger, you should definitely invest in a good dwell meter and feeler gauge set.
But inspect that cam and other things too first, since changing to electronic will negate their use 99% of the time.
You should also test the distributor's bearing surface and shaft tolerances by hand at least, by removing the rotor and pushing the shaft end side to side and up and down to see how loose it is.
There should be almost no sideways movement from pushing (though it will twist easily against spring pressure of the advance weights) and very little up and down movement.
And while you're at it, twisting the upper part with the cam on it will give you a feel for how the advance mechanism is functioning. If it's smooth and tight when you twist, that's a good sign. If it's floppy, chunky and sticks at all, then it's time for some serious TLC because your spark events will never be consistent or accurate.
Paul