Cartel vintage Sub cases, like most budget cases have the serial numbers etc laser etched. A Cartel case isn't going to get passed someone with even fairly limited vintage Sub knowledge - aside from the laser etchings, the tube is in the wrong position in the case, lugs and crown guards will not be correctly shaped etc.
But besides all that, What are the engravings in between the lugs like? When I see someone wearing a Rolex, I look at those engravings (can be seen a mile away) and they are the sure tell!
Not everybody has your level of expertise when it comes to inter-lug engravings.
But yeah, on a Cartel they're laser etched, and that's what the look like.
A Cartel case isn't going to get passed someone with even fairly limited vintage Sub knowledge - aside from the laser etchings, the tube is in the wrong position in the case, lugs and crown guards will not be correctly shaped etc.