If you drove for around let's say; 3500 kms, and at the time of drainage, its colour, viscosity, "feel", "smell", etc. was exactly same, as was when it was poured brand new, then IMO, oil may be FAKE!
A Good, authentic, fully synthetic engine oil will be brown, brownish black, or black, and as thin as water, at the time of drainage, and when it has been driven for around ~4500 Kms / more.