Those do indeed look like target shooting medals. Shooting clubs here in Germany hand those out to their members. They have no official meaning as far as I know and just represent that a shooter has scored well (not sure if there are any real criteria to be met). Oberpleis is a city at the Rhine river so that would fit as well.
If you put the German term "schützenmedaillien" (target shooter medals) in a search engine you'll get fairly similar results:
https://duckduckgo.com/?q=sch%C3%BCt...ages&ia=images
And here for "Schützenorden" (which means the same):
https://duckduckgo.com/?q=sch%C3%BCt...ages&ia=images