Yeah. This is what you do for any Pokemon that you have just received. It all depends on it having no experience and no EV increasing berries or vitamins.
Take the Pokemon into a Wi-Fi Battle at level 100.
Write down those stats.
Go to a site with an IV calculator*, insert the species, nature, and stat #s to be properly calculated.
*I use Psypokes, but any of them out there will do.
These are commonly called IV battles. After it's done, you either both agree to run away (resulting in a tie) or disconnect by shutting off the DS' power (Safest way). It's pretty important to have a real-time communication with your battle partner (IRC, IM program, etc...)
An alternative is to go into PBR which auto-levels it to 50 in any type of battle, or to rare candy it up to at least level 30. The higher the level you can calculate at, the better the IVs estimation will be.