First of all, I have no idea. I'm not an expert, nor am I a consumer of such goods. But two things strike me as fishy about it.
#1: I do have some expertise in typography and commercial art, and my eye is immediately drawn to the conspicuously off-center lettering in the skulls. I would expect the letters to be more symmetrically placed. To me, the design is slightly off-putting and sloppy. The lettering on the label looks to me just like it would on any authentic article. But... I also know that authentic labels are sometimes smuggled out of garment factories and put on phony articles.
#2: I tried to google all kinds of combinations of "givenchy/white/skull/bones/tee/tshirt/etc," and can find nothing like this design out there. Skulls, bones, and stars are very common motifs in their designs, but I was kind of intrigued that not a single image result looks like the shirt you've pictured.
If you like it, and you think the price is fair, then there's no reason you shouldn't buy it. But if authenticity is important to you, I'd ask where and when it was purchased, because it certainly could be a fake.
