I believe it was the 9mm model of SIG's poly line - I had the 2340 (40 S&W) model and it was a great gun. It looks like both the 2009 and the 2340 were discontinued and replaced by the 2022 (available in 9mm, 40, perhaps others). The difference between the 2340 and the 2022 is the 2022 has a standard accessory rail, while the 2340 (perhaps the 2009) had a proprietary rail. Does yours have a non-standard rail?
Anyway, as I understand it, all the other parts are the same.
You got a good deal; shoot it and enjoy it - some (even SIG fans) maintain that the poly pistol has a better trigger than the metal-framed guns.