I can't tell. He seems to have a similar hand position in the "Live Action" image from the 1896 GAH at Live Birds, and was using a pistol grip then https://books.google.com/books?id=rUMhAQAAMAAJ
The “Fred Gilbert Specifications” were drop at comb of 1 3/8 inches; at the heel, 2 inches; length from trigger to heel, 14 1/4 inches; trigger to toe 14 1/2 inches; and trigger to center of butt 14 inches; with a full pistol grip and 30-inch full choke barrels.
Order Book No. 41 records BH SN 83855 placed into stock in Jan., 1896 consigned to Fred Gilbert. The stock book lists a D5 hammerless, 0 extras, Straight Stock, 12 gauge, 30" barrels, Damascus barrels.
November 23, 1901, The Sportsmen’s Review, in an article written by “Gaucho” (Captain A.W. duBray, Parker Brothers shooting professional & traveling salesman from 1884 to 1926) entitled, “A Few Remarks on Some Celebrated Guns,” du Bray lists some prominent shooters and Gilbert was reported to be using a Parker with 30” barrels; 1 3/8” DAC; 2” DAH; 14 1/4” LOP with a Pistol Grip (which appears to be his Smith; his BH had a straight stock).
