No maker's mark on silver flask

My father purchased this silver flask in 1980. The note on envelope says “tested pure silver possible 1870-1875”. He paid $20 at the time. The flask is 4 inches long an 2 inches wide. I don’t know if the markings on it are a maker’s mark or just an engraving. Any information would be greatly appreciated.
Thank you,
Chermical
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Hi there and thanks for joining us. The writing is custom engraving and not related to the maker. I don’t see any maker or purity marks. Try lookin g on the bottom or perhaps on the inside of the lid for other marks.

Regards,

Uncle Vic