By "early" I meant it still had the snap-on/-off forearm.
The graded smallbores generally had the snap-on/-off forearm from their introduction into about 1915/16. My 1913 vintage A-Grade --
CE-Grade 200109 --
Nothing of course is absolute, as 200002 has the Deeley forearm --
From my observations the Fox & Kremer or F.T. Russell style snap-on/-off forearm was generally used on the 20-gauges up to near 200600 and the Deeley was firmly in use by 200700. The engraving had firmly gone to the Gough style by 200300.