From what I read in the PDF in zooks link page 8-9, they changed the targeting law so you can target them but may not keep them, did I misinterpret that?
It varies with border waters but the current MN inland sturgeon season is from mid June though mid April, catch and release only.
https://www.dnr.state.mn.us/fishing/seasons.html
It’s my understanding, both through that article and in other reading, that besides Rainy River/LOW and the Croix, there was no native sturgeon population in MN as of 20 years ago, so it’s unlikely the fish being caught in URL were an older population.
Also in the last section of that MCV article, it talked about how sturgeon fingerlings released in Big Stone in 2014 were already 17″-24″ by fall of 2016 so it’s easily conceivable that the 7 yr old URL fish are pushing 40″ or more.