If they were to go Ohio Vintage Days and see what really nice KZ's and Z1's sell for they might not do that.
The guy who has this is more-interested in building a bike for the street than doing a stock bike restoration. He has a Hyabusa w/N.O.S. he bracket races. This is going to be a street cruiser that's different from another of the same vintage. It's not going to have a hairy engine, just a bit of a tweak, the effort is being put into the suspension. They've already swapped out the front forks and wheel and this will be an aluminum swingarm and a wide rear wheel to run radials. Functionally, it should work much-better than the stock KZ1000 suspension. The guy doing the layout is just finishing-up a 'Slingshot' GSXR 1100 which has a big-bore motor, and a VFR 750 single-sided swingarm. It's running Dyna coils, Dyna ignition, and Lectron carbs. They like the Suzuki GS 1100/1150 and the Kawasaki Z1, KZ900/KZ1000 and GPZ 1100 engines for street builds and for drag bikes. He does do restorations if a customer wants that. He just did a CB 500 and a CB 160 for the same customer, who finds unrestored bikes, and then brings them in for the work. The CB 160 was in storage in Las Vegas for 24 years before he found it and had it shipped to south Florida. Right now there's also a Honda 305 Dream that just came-into the shop, from Indiana, the Hyabusa owner brought it down. It's awaiting its turn. The white bike behind the CB 160 is a heavily-modded CB 750 SOHC big-bore bike, now 900 cc.
Here are several bikes another friend did, if you like the close-to-stock look. The first two are for-sale. Take a close look at the Z1 with its J-model KZ 1000 top end, and the aluminum wide spoked wheels, allowing use of radial tires.
A couple of heavily-modded KZ's shown in St. Augustine FL at last year's Riding Into History event, held each May (
https://ridingintohistory.org/) . These were done by a retired Yamaha factory mechanic whom I've known for 30+ years.