Hi, glad it helped!
The photo is posted on a web page titled Romeriksbilder. Many of the other photos are interesting as well.
The caption information likely came from the person who donated the photo to the museum. The family may not have dated the photo at the time, perhaps many years later. That's the way it was with most family photos! Before the days of digital dating.
Since your mother-in-law confirms it is Walter and Stanley in the photo, the year must be a mistake.
In a way the photo illustrates a person emigrating, then returning home for a visit. It's emblematic of an experience shared by many. A wonderful photo. :-)