Okay, here's a late arrival and anomaly:

Centurion Sport DLX mixte

M5D 01189

'Made in Japan' sticker on BB, 'Quality from Japan, Designed in USA' sticker on seat tube, so the M evidently doesn't mean a Taiwanese build.

It would seem to be a 1985 bike, but the 1984 catalog on Sheldon's site describes the Sport DLX as having a Cr-Mo frame, while this one is labeled as having a 'Tange Butted Hi-Ten Steel' frame. Similar label on the fork.

Someone, possibly the Turin Bike Shop in Evanston (n of Chicago) where the bike was purchased, substituted a Maillard/Wolber Super Champion rear wheel with QR, and a Suntour AR RD for the Suntour 7 that was OEM. FD is an odd boxy US-made 'Excel', probably also a replacement, brakes are Dia Compe sidepulls.

Not bad for a cheap little bike.