Goods is not slang; more the opposite, really, although it could be used by criminals in a slightly tongue-in-cheek way. Other names for stolen or smuggled goods would be merch (short for merchandise , also a tongue-in-cheek reference), swag , loot (for money only), stash , stuff , perhaps takings or proceeds , and probably many others that I would know if I was a crim :-) Yes, "Keep an eye on the goods" is a good line for a criminal to say. It also depends on the nationality of the crims.
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