Piston rings

Hello KZ heads I need to pick a little bit on your brain
Just got a Kz1000 engine that was put away in a basement in 1979 with less than a 1000 miles on it, unfortunately when I did a compassion test number 1 -4 cylinder were throwing 120 and 1-3 cylinders 0 so I decide to open the head as and check it out and everything looks like just came out the factory very little wear and tear on the cams and seats and almost no carbon on top of the engine.
There is some rust marks in the intake valves so I will check the valves.
there are no marks or scratches in the cylinder jugs but obviously the piston rings got stock in the pistons my brother is saying that it might just need new rings, gasjkets Rings and good to go.
we Will still take it to a friend that use to prepare and race the bike back in the day to get his opinion today but if that its all it needs the question is where to get the STD rings as they were discontinued long time ago or which one its the best aftermarket option for the rings, I am not a fan of aftermarket parts but I need opinions in this topic.
My brother says that definitely the original rings can't be reused.

No eBay APP ID and/or Cert ID defined in Kunena configurationI'd look for someone with a bore gauge and a good micrometer so both the cylinder and pistons can be measured. You need to determine bore out of round and taper, and piston to cylinder clearance. Typically, if the out of round and taper are .001" or less you can go ahead and rering. Piston to cylinder clearance is less important but I'd be leary of going much past .005" in that regard.

If it is truly a 1000 mile motor chances are the rings are fine and just gummed in the pistons. You could just put some fuel in the bores and leave them to soak but personally I would strip the top end and check everything is in spec.
How sure are you the milage is accurate? Why would anyone mothball a bike after only 1000 miles?

Thanks for the reply, I opened the head and the valves are not closing due to some rust but everything inside looks new no were at all in the cams or the seat of the cams like new, no yellow coloring.
The story is that this guy bought a 1979 bike and fell on the left side, got so scared about riding that he never did it again and the bike sat at his house for 10 years after that he started to sell the bike in parts and his neighbor that had a kz bout everything he had left including the engine, He never got need to use the engine and it sat in his basement. He sold his bike so did not have use for the engine.
unfortunately they did not seal the inlets and humidity did its way in.and some rust its holding the valves open. I did open the filter cap and everything looks so new there is not yellow coloring.
A mechanic that its a friend of my brother told me to put disassemble the head and have clean and do a valve job and new valve seals and new rings and gaskets and should be good to go.he will also check the clearance of the pistons and cylinders.

If it's a true 1000 mile motor I'd pull the cylinder block clean the ring's and ring grove's in the piston's do a LIGHT hone and put it back together with a fresh valve job.

Are those NPR rings a high quality rings? I remember that some not OEM ring did not use to last very long. I just want to make sure I don't have to open that engine for a very long time. I ride once in a while so this engine will be with me forever. I guess.