I just picked up my new-to-me Mini a couple of hours ago.
182-74xxx range makes in 1981 according to RENE. Stainless with wood hand guard (which I prefer the looks of) but new enough to have the button to hold the bolt open.
Bonus is it came with 4 Ruger brand 20 round mags, a factory folding stock and a plastic hand guard too!
Only have an outdoor range here and temps the next week or more to be single digits to teens so ..... it'll be a while to warm up the barrel.