Locate the speaker which can be found in the back of the amp. Find the source code stamp, which is a series of six or seven numbers, that will be stamped on the speaker. The stamp can be found on any part of the speaker, but it will be readily visible no matter the location.

How can you tell a real Gibson acoustic?

How to spot a fake Gibson:Measure the guitar to check if its undersized. Examine headstock and headstock logo to determine that they match those of authentic Gibson guitars.Check to see that all pearl is inlaid.Check that Les Paul model script is always in cursive.Verify that theres not a 3-screw truss rod cover.More items •4 Sep 2008