Yup. Definitely not the usual Rosa fare.
He made it in 1970, when he was still in college, and a friend got the pages, to try to get them published, but obviously without success. They then lost contact, and the original pages were only found again in 2010, despite Rosa's own efforts to find them over the decades, when Egmont pushed for them to be included in the collection.
There are also other comics he made for the college newspaper, like an adaptation of 2001: A Space Oddyssey, with other students as the cast.
Here are the first 3 pages of "Return to Duckburg Place".
On a later page Gladstone shoots himself in the head. I was very surprised, that Disney would allow this to be published. And also Don Rosa having even made it in the first place.