Unless the cyl walls are stained or funny looking from sitting or have some other problem, I personally would just reassemble it, clean and lubed like a new motor. It sounds fairly recently rebuilt, and with your usage plans, it sounds great as-is.
I too get the temptation to make things perfect even when they're close-to-perfect, but I've learned to resist! Unless there's other factors, the net gain here sounds too small to be worth the effort and cost.
Or if you don't want that terrible old motor, give it to me, I'll dispose of it properly for you, no charge... :-)