Instead of finding a 2627 in there, it's actually a 2616.2H.
But IIRC the 2616 should NOT have a DAY window. Thing is the day did change to Friday (today) from yesterday's Thursday, so implying that the day function is working in this watch. So does the 2616.2 version support the day function too?
I cleaned up the watch with an old toothbrush and some liquid hand soap, after removing the bracelet. Yup, there's loads of gunk in between the lugs, and now the watch looks much better
I'm quite amazed by this watch's power reserve. I haven't worn it, shook it up just a few times yesterday (last shake was at about 7pm yesterday, less than 10 times), and the watch only stopped this morning at about 9am