First, be sure to do a little online digging before buying a secondhand designer item.
It’s never on the side of the bag.
double-check the serial number is in two stacked rows and doesn’t include any letters.

Next, check out the bag’s hardware.
If it feels light and flimsy, it’s not authentic, perLove that Bag Etc.
And if your bag has a metal zipper, it should be flat and branded with the word Gucci.

Another tell-tale sign of a forgery?
The two legs of the U in Gucci are the same width.
In an authentic bag, one side of the U is wider than the other, reportsBagaholic 101.