I'm NOT an expert, so kinda talking out my @$$ here, but I swear I read that Hermès ties always have 4 digit serial numbers and are rubbed just off-vertical at 11 to 5 o'clock. But they look pretty legit otherwise.
Anyone with more experience than me care to verify?
They have two, three or four digit numbers - sometimes seven or eight for the woven silks. Frenchy's are a limited edition though and walk to the beat of their own drummer. No question about legit-ness.