Green’s Dictionary of Slang

a fashionably dressed person.

1912		E. Pugh Harry The Cockney 191: I fair hate the sight of the people next door. A lot o’ superior haw-haws and niminy-piminy clothes-props!
1914		Bulletin (Sydney) 1 Oct. 36/2: The girl is one of Brisbane’s smartest garment pegs, and one dewy morning she tripped forth clad, plus sundries, in spats.
1920		‘Sapper’ Bulldog Drummond 71: The superbly dressed young man whom he had discovered already was merely a clothes-peg calling himself Darrell.
1930		N. Lindsay Redheap (1965) 252: ‘Oh, to hell with him anyway,’ he said. ‘He’s only a damned clothes prop’ .