First post about Møllerstufossen: https://andersgoliversen.com/blog/2022/05/16/mollerstufossen/
Some of the figures at Møllerstufossen reminds me of goats more than moose or deer, such as this one:
Møllerstufossen is one of two areas with petroglyphs in Innlandet county, the other one being Moelv which has some figures that also look like goats to me: https://andersgoliversen.com/blog/page/5/
There is a lot of uncertainty when defining the exact age of petroglyphs, and if some of the figures actually represent goats this would exclude the carvings from being older than 4000 BC. since goats first came to Norway around 4000-3000 BC.
It is possible that petroglyphs at Møllerstufossen and Moelv all meant to represent moose or deer, and what I interpret as goat horns are moose/deer antlers lacking details or very long ears. But there is a figure at Møllerstufossen with what is more obviously moose antlers, which makes it more unlikely that they would draw antlers this way.