Magazines are a spring arrival. With all the major OEM mag manufacturers so backlogged, it is a struggle for any company these days to have enough mags to go with their pistols in the box, let alone spares, so lots of shipments in late 2014 and early 2015 have not had spare mags even from companies who are usually very easy to get (S&W et al). Most things have had spare mags show up on subsequent shipments about 2 months after, like with Ruger SR9, SR40, and SR45 handguns in January... pistols showed up in December, mags showed up at the end of January, and now SR9/40/45 pistols are slated to show up again. This is the way of things at the moment, at least until OEM mag companies get out from under their backlog.
Edit: Additionally, we'll always post spare mags in the thread with the guns if they arrive at the same time. If they don't, and you can't find them on our site from prior shipments, it unfortunately means we're out of stock on spares.