Green’s Dictionary of Slang

(US) square-toed shoes, usu. work shoes.

c.1943		‘Bill O. Lading’ You Chirped a Chinful!! n.p.: Lil Abners: Army shoes.
1959		Air Force Blue Book I 155: [...] the blue skirt and shirt, thick blue socks, and field boots known as L’il Abners, usually issued on the second day.
1983		E. Sturz Widening Circles 16: Lil Abner construction boots, French cut shirt [HDAS].
1990		(ref. to 1945) A. Bérubé Coming Out Under Fire 56: There were all these dykes sitting around with their feet up on the table in fatigues with Li’l Abner boots.
2002		M. Mangham Things Left Undone 172: Cipher came down the sidewalk wearing his usual blue jeans, L’il Abner boots and white, tight T-shirt.