With that s/n it's most likely a pre-13 gun and, if so, not a Field grade. As a project gun it's not because 1) the barrels are whacked and you'll never find barrels that will fit without a lot of fitting; 2) pre-13 stocks are almost nonexistent used, and;3) the salesman does not know much about Smiths because there is no such thing as a Series E (probably an ejector gun).
It's a parts gun---not a project gun.