Front of the Box
On the front of the box there are a number of issues on the fake Majin Vegeta. The first and easiest indicator is the location of the Dragon Balls. On the authentic Pop! there will be a Dragon Ball in the pattern right above the word Dragon Ball. On the fake you will not have a Dragon Ball in the pattern.
Alternatively on the fake, you will notice Dragon Balls in the pattern behind the Pop! nameplate. On the authentic Pop! there are no Dragon Balls in the patter.
Next, take a look at the Majin Vegeta character artwork. On the fakes there is an error where there is a gap between the white trim around the window and the illustration. On the authentic Pop! you will not have this error. On the fake you will also have poor pixel quality and pixelation on the illustration.
The Over 9000.com Sticker
Take a look at the skin color of Majin Vegeta. If you have a fake you will notice that the skin tone has more of a red tone to it. The black scratches on his face also look much closer together. On the authentic Pop! you will have very clean and spaced out scratches. If you look at the eyes, the real Majin Vegeta has very clean lines while the fake has a lot of spill over onto the face.