T stamp location

Hey everyone,

I recently purchased a B30 (2015/T stamp) from a second-hand seller, and just received the bag. I see conflicting information online about where the stamp should be, for example this site says from T stamp onwards the stamp should be on the interior of the bag but this video says that it should be behind the strap for 2015.

The bag I received has a T stamp behind the strap -- are there 2 versions of the bag, one for on the interior and one for behind the strap?