The materials are certainly similar to those Marxhausen used in many of his works, and the time would be right. This would have been used in chapels during the years when Marxhausen was teaching at Concordia. When Serk was a student, Marxhausen was still the only art prof.
I would wager that this was by Marxhausen. At the very least, it must have been done by one of his students, using the techniques he taught in his classes.