Thanks for the info! It's definitely an AA-operated flight.
Just found this page on Delta's own website, which suggests I'd probably get SkyMiles, but definitely not Medallion Qualification Miles.
https://www.delta.com/content/www/en...orean-air.html
Looks like I'll be taking Delta's ICN-DTW-DFW then. Just short of silver and this would put me over the top.