Green’s Dictionary of Slang

(US) dressed up.

1921		Marshall News Messenger (TX) 30 Sept. 8/3: Adams [...] was all duked out in his new uniform and ready for business.
1922		Chicago Trib. 7 Nov. 17/3: My idea of the Height of Affluence is a guy all duked up in knickers out in the backyard with a 15 cent golf ball.
1935		Salt Lake Trib. (UT) 25 Nov. 13/7: Today he was duked out in a golden brown great coat with a blood red carnation.
1935		News (Adelaide, SA) 14 Dec. 6/5: ‘[A goat] [a]ll duked out in fancy horns next to his bland, powdery face. [...] He reminded me of a dissipated old woman trying to knock off 40 or 50 years!’.
1936		M. Levin Old Bunch (1946) 48: Foxey was all duked up wearing white duck pants and a silk shirt.
1940		Palm Beach Post-Times (FL) 5 May 18/5: It’s the Ba,bino, the old Sultan of Swat, Babe Ruth himself, all duked out in a topper, morning suit and boutonniere.
1949		Hal Ellson Duke 98: He was all duked out.
1951		Detroit Free Press (MI) 15 Mar. 40/3: [advert] 1949 fords — I’ve got three of these all duked up like Mrs Astor’s pet horse;dripping chrome and sunsades and they run like scared rabbits choice of color at $1,287.
1953		J. Thompson Savage Night (1991) 83: He was all duked out in a hard-boiled collar and a blue serge suit.
1978		S. Longstreet Straw Boss (1979) 374: All the damn snooty limeys with their duked up, posh guests.