Twice the same maker's mark, a clover in outline with a V-shaped stem, could point to Groningen. The existing literature on Groningen silversmiths doesn't mention any master who used a clover as his mark. The horizontal handles also don't point to Groningen.
A clover was a favorite maker's mark and was used by many silversmiths in various cities. The lack of a city hallmark and date letter makes attributing the maker's mark difficult. The location of the two marks certainly stands out. In short, I don't trust the marks; they could be fictitious or pseudo marks.