Carse Antiques has dated this piece to the 1700s.
This example having the initials M over WM over AM. Unfortunately the hallmarks on this spoon are rubbed but the IB mark is clear and the rectangular armorial mark can be made out under a strong magnifier.

Having come from a private collection this spoon also comes with a detailed double sheet of information about the maker from a review of the Lyon and Turnball Scottish silver sale from 16th August 2017 where a similar spoon was sold with slightly better marks.

James Brown was known to have been working in Perth in 1724 and is also known to have moved to the north east part of Scotland with his son Francis looking for work. There are spoons known by James Brown with the town name PERTH stamped on them but not the Perth double eagle headed punch mark. There are only a handful of spoons known with this rectangular armorial mark which has been pretty much attributed to Fraserburgh due to its very close resemblance to the family Fraser and the Fraserburgh's town seal.
The spoon is in very good condition for such an early Scottish spoon apart from the rubbed marks.
SIZE; 8 1/2" long
CIRCA; 1725 - 1735
Carse Antiques has dated this piece to the 1700s.
You can view the stock and full dealer information on the Carse Antiques Profile Page
Carse Antiques is a registered member of LAPADA