The serial number is one of the first places to start for how to date a Gibson Les Paul guitar. It should be on the back of the neck at the top just between and above the tuning machines. Take a look- if your serial number is more than 6 digits then your guitar is no earlier than 1976.

How can you tell a fake es335?

0:557:48HOW to SPOT A FAKE ES 335 or ES 355 from China - YouTubeYouTube