Adding some mark images from tablespoon...engraved in 1959 after Olsens had taken over Magnus Aase:
My suggestion....Mark 1 (alleged "IN") might be explained by referring to the "SOELBERG" thread. That is, the hemispherical mark here could be a small mark version (sans the seven hills) of the Bergen semi-circle town mark used in earlier times. That would make the "N" a stand alone second mark possibly designating "Norway"...thus a combination town & country mark created by the Aase firm for their own useage. Too far fetched???