The chainrings are the second set I've installed on them, they are the Race Face made in canada 7075 aluminum with steel granny if I recall probably not many miles on these chainrings. This crankset is in good condition, mainly just scratches from my shoes, no deep scratches or anything like that. The worst thing would be on the back of the drive side near the base (see photo 10) that is a scratch from a tool.
I installed these on my hardtail this year with a new chain and 10 speed cassette and they were great. 9 speed chainrings work just fine with 10 speed chains. They have syncros crank-o-matic crankarm extractors installed (sell for over 60 dollars on this site), I do not have a spanner wrench to remove them though I tried using a circlip tool but its not strong enough nor made for this. Lets assume they are not removeable as they have been in there since the 90s. They have the 6/4 titanium crank bolts. Honestly it is a sweet free upgrade to the cranks as it negates the need for the extractor tool and just requires an allen wrench. Feel free to ask any questions or if you want a better picture of a specific area of the crankset. Good history of kooka cranks at bikepro cant post link unfortunately. The item "VINTAGE KOOKA BILLET SQUARE TAPER CRANK SET" is in sale since Saturday, August 28, 2021. This item is in the category "Sporting Goods\Cycling\Bicycle Components & Parts\Cranksets".The seller is "gandc40" and is located in Destin, Florida. This item can be shipped to United States.