Identify 1980's Bianchi? Can someone please help me identify this bicycle?

My mom has had it in storage for ages&nbsp;&ndash; I believe it's from the 80's or early 90's. I'm not sure what is original and what was changed... But you all probably know far better than I, so here are some photos!

Thanks in advance :))

























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The bike might be the a 1981 Rekord "W" Strada, at least this catalog page shows a very similar photo, but no exact parts list:

It might also be another Bianchi mixte-style frame with components swapped, i.e. flat bar to drop bar, which makes identification harder.

Or it might be a late '80s (possibly 1986) womens Bianchi Strada, as shown in this question. Note that serial numbers on both bikes are very close: 51027534 vs 51027563.