Personally would have trouble attributing this mark, or for that matter, the (925/1000) [Evon only shows the (925/000) variant of the mark in her book] to a Marshall Field wholesale workshop, especially since she notes that the workshops didn't actually open untill 1903 and pieces found with the (925/1000) show up in the 1901 Daniel Low catalog, and when those also bear a retailer's mark, they seem to be East Coast firms, can't recall seeing any Chicago or the MIdwest retailer marks. Simple hammered pieces similar to the (925/1000) are sometimes found with a similar 'STERLING' mark, including the little 'tail' on the 'G', can't say whether this piece or the (925/1000) items were made by the same maker, but have seen more than one holloware item with marks like this, also bearing the mark of the New York/New Jersey based Merrill Shops...
Note similarity in style to the Merrill Shops piece here:
http://www.925-1000.com/forum/viewtopic.php?t=34216Merrill Shops marks:

~Cheryl