I would like to add that the script used for the 1836 does not look like a pattern hallmark, it looks like engraving script, like what was done for the monogram. Pattern numbers are usually in a block font like the name of the silversmith is. I would not be surprised if that is in fact a date, perhaps to commemorate a special occasion like a wedding. It would not make sense for a silversmith to have a pattern number engraved, rather than just stamping it in with his maker's mark.
That said, one problem with monogrammed items is that unless they are from your own family, most people don't want someone elses initials on a piece and they can be hard to sell. Also I don't think this is necessarily a grapefruit spoon since they are serrated at the end of the bowl and they were apparently invented in the 1940's by a guy name Jack Yolles. (further research is needed to see if that info holds water). Although the shape of this one is unusually pointy, I think it is just the style.
