SMD LEDs normally have some kind of marking like the following image from here indicates:
The site states
The CATHODE lead is always the lead to be identified with ALL LEDs, including surface-mount LEDs.
There are definitely manufactures that do NOT follow this scheme like this one from CREE.
We recently had 300 PCBs manufactured where each had 32 LEDs of those. However, the assembly house placed all LEDs in reverse. The first thing we obviously did was looking at our board layout.
If you assume that always the cathode is indicated, the footprint is correct. However, it is not consistent with the marking of the actual LED that was mounted. The manufacturer probably just looked at the matching markings.
Long story short, the manufacturer checked their production and "admitted" that it was their fault. Actually, we worried that they just "but the marking says otherwise".
This could have ended up in a long discussion about who's fault this was, so:
Is there a standard that defines that the marking actually HAS TO indicate the CATHODE? Has the assembly house to double check something like this?