Looks OK to me.

Yeah, since posting I found a photo of the off-center T shaped key.

Did you check compression?

Sort of. I do not own a gauge; I will have to decide if one is worth
buying for this. I do feel it on my finger if I place it on the spark plug
hole not to mention hearing it wheeze at the exhaust. (Muffler is off for
now.) And it's harder to turn with the

Let's say the compression is bad. Would that prevent it from running at
all (as opposed to running badly or weakly)? What would be the likely
cause? Broken ring? Now that I think about it, when I had the head off
the cylinder did have some scuffs.