Busted off TT by the looks of it. I wonder if there is a lot of slop on the pivot post too - it's another job worth sorting if the thing is coming to bits anyway, although a fiddly one. The problem is that wear there causes poor opening, promotes arcing at the points and very often upsets the firing interval between the two sparks by several degrees.
The buffer spring needs sorting, the fixed point is 'unusual' in having had its hex turned into a knurl(!) and it really should have its retaining clip and little titty thing to help keep things straight. The clips can often be had - or in the worst case a bit of junior hacksaw blade cut & ground to suit, punched through to make an 'ole and clouted carefully to make a register for the tit does a neat job that's almost indistinguishable from the original (with a bit of patience!). The pin may also be available, or a small (6 or so BA) screw and shallow nut can serve if the pinhole is tapped, although it may be tight if there is an (optional) auxiliary earth brush meeting things from the other direction.
As to winding recipes and TT's query above . . . very occasionally I have seen (rotating) mag coils wound to produce a simple HT resistance as high as 8000 ohms, but never anything like 19K. But I agree there are car-type coils which show much higher figures, certainly, and static coils are quite often close to 5 figures on some magnetos. 'Normal', if there is such a thing, seems to be from 4500 to maybe 6000 ohms depending on who's done it. Commonly, 5000, near enough spot-on. Some of the competition windings seem to have had a bit more wire on back in the day judging from from some of the readings, but AFAIK the majority of winders treat all K series coils pretty much the same these days.
The slipring isn't worth persevering with. It probably leaks, will almost certainly be prone to tracking and so on, and its surface is rough enough to eat brushes I'd guess. I wouldn't be at all surprised if connectivity inside was poor and responsible for the poor HT reading, but the only way to find out is to get it off and measure from the bare spike of the coil.
I think the mag needs a fresh going over to be honest, to eliminate the risk factors one by one and get it back to full health!