Green’s Dictionary of Slang

carrying a gun.

1929		E. Booth Stealing Through Life 249: We thought you were rodded up.
1931		D. Runyon ‘The Old Doll’s House’ in Runyon on Broadway (1954) 63: Lance is by no means rodded up, because a rod is apt to create a bump in his shape when he has his tuxedo on.
1936		R. Chandler ‘Guns At Cyrano’s’ in Red Wind (1946) 209: It’s okey to frisk me. I’m not rodded.
1950		Goldin et al. DAUL 180/1: Rodded up. Having one or more revolvers concealed on one’s person.
1979		F. Norman Too Many Crooks Spoil the Caper 31: The Metropolitan police do not carry firearms unless [...] they have good reason to believe the tearaways under surveillance are rodded up.
1984		‘Derek Raymond’ He Died with His Eyes Open 182: ‘Are you rodded?’ he asked in a pathetically artful way.
2000		(con. 1940s–60s) Décharné Straight from the Fridge Dad.