gtx 770 2gb gigabyte oc do i overclock it or its already overclocked

Solution
The answer is both. Not only does it come overclocked, but there's a chance if your thermals are good, you can overclock it some more.
my rig
INTEL CORE I7 -4770K
2 GIGABYTE GTX 770 2GB DDR5 OVERCLOKED EXTREME
3 RM Series™ RM750 — 750 Watt 80 PLUS® Gold Certified Fully Modular PSU
4 CORSAIR HYDRO SERIES H100I HIGH PERFOMANCE LIQUID CPU COOLER
5 GIGABYTE GA-Z87X UD4H SOCKET 1150 PROCESSOR 4TH GENERATION MOTHERBOARD
8 WINDOWS 8.1 PRO
9 Corsair CMZ8GX3M2X1600C8B Vengeance 8GB (2x4GB) DDR3 1600 Mhz CL8 XMP Performance Desktop Memory Kit Blue
10 CASE(Cooler Master Storm Trooper Case )
12 WESTERN DIGITAL 1 TB SATA 7200RPM 64MB CACHE INTERNAL DESKTOP HARDDRIVE BLACK WD1003FZEX
13 DVD RW