a couple three

[Jarek Hirny]

Hi,

on p 49 Nate Privett says "They're meeting right down the El line a
couple-three stops [...]".

But, but, but. I looked up what precisely "a couple-three" means and on
http://www.urbandictionary.com/define.php?term=a+couple+three it states
that this term originated in 1960s. Definitely not the time of Nate's
quotation.

Is it an older term? Urbandict is wrong? Or, some Pynchon's slip of the
tongue? Which I highly doubt thanks to his generally praised ear for 
american idiom...

thanks,
Jarek