HK USP 40C Mag question

[Austin]

As the title says I have a question regarding magazines for the HK USP 40 Compact.

Mine came with a 7 round magazine if i remember correctly. But now I see on the site that they have 12 round mags. Link Removed

I also see where I can order 12 round mags from Botach: http://www.botachtactical.com/hkpisrifmag.html

Is mine an older version or something that wont take these mags (had it for 10+ years)?

I hate to spend $40 on a magazine that wont work, so I am asking here. Does anyone know what the deal is with this?

Thanks in advance