A good way to get around this when writing would be to use the word בשביל [bishvil] or עבור [avur] (both meaning "for the sake of"). Also remember, though, that context is important; if someone is shopping for you, and sends you a text asking what sort of socks you want, and you respond, they probably wouldn't think that you want 12 socks "for the boys" :)
IMHO (a native speaker, probably like BezalelP) "pairs" is not implied. If someone said this sentence to me I'd think they are sloppy, and should say explicitly שניים עשר זוגות or שישה זוגות. If I'd have to guess what they meant, I'd guess 12 individual socks (six pairs), which isn't far fetched if they're all the same color... But I wouldn't be comfortable about this guess.