I visited the Arsenalen Museum near Stockholm this summer, they have an unmodified Strv m 21 on display:
More pictures here:https://www.flickr.com/photos/massimofoti/sets/72157646628902666/
Since I am here, I post also the Strv m 21-29 from Munster:
More pictures here:https://www.flickr.com/photos/massimofoti/sets/72157633224296936/
Both museums have excellent collection and definitely worth a visit
Massimo