No easy to spot fake clubs.
The best way to avoid it is to buy from an authorized dealer.

Today, fakes item are reproduced with realistic cosmetics and fonts to not specialized persons.
But, one think is sure, the quality and performance won’t be the same.

On internet resale platforms is the good way to get screwed. Not always. If it is to good to be true, it is maybe not true.

So caution,

Only buying from certified Titleist vendors is obviously the best. All Titleist products should have serial numbers that you may be able to verify by calling customer support.

However, I highly recommend buying from a reputable Titleist vendor that way if the product is defective in any way Titleist will work with you to make things right.

If you buy your equipment from an authorized Titleist dealer, then you won't have to worry about "fakes".

I’ve been wanting to try the new GT3 driver, a friend of mine picked up a demo from some mom n pops golf shop, and told me the guy would sell me one if I liked it for $275…. I took it to my range and knew something was wrong right away . I plugged in my shaft, and first hit it felt horrible and sounded worse. I looked at the face and my ball mark was almost dead center. For reference I’m a 1 handicap. I hit a second ball, and the club felt dead. Again ball mark pretty close to center of the face. I gave it back to my friend and he later found out it was a fake, a replica . So I’m still looking to try a GT3, I currently play the TSR 3 in a 9 degree, with a Tour AD IZ 6x shaft.

You answered your own question?? If it is too good to be true, …it isn’t. Large resellers like 2nd Swing and Global Golf guarantee authenticity on their used clubs, if you don’t want to get fitted for new. But no real GT driver will be so far under $500.

The price of the new offerings from Titleist is fairly standardized with Price maintenance agreements. If someone is selling it for substantially less than that the only explanation has to be it is fake or it is stolen. How could the real thing be acquired legally and the sellers still make a profit at the discounted price?

It's always buyer beware from online sites. If purchased from EBay or other's just make sure you can return it to seller. I would check local Golf stores. There has been a GT3 for about a month at the Golf Galaxy I frequent. People will trade in a lot of things now that the "new" equipment is starting to drop.