It's still possible!

It'd help us to open the watch, naturally, but we can still rely on pics. Make no mistake though — the watches can be 99.5% perfect, but (at least for the watches we're handling, which have high values) the compromise in manufacturing processes is spotted one way or another

It's worth pointing out that the discussion about replacing pieces of a fake watch with authentic pieces (making a so-called 'franken' watch, as rep watch connoisseurs call it) is a totally separate discussion