I tried calling into a couple different AD to order a Deployment Clasp for my Speedy. Both AD's wanted the Serial # on my watch, while others didn't.

Is there a reason an AD would ask for my serial. I declined, because it seemed sketchy, but now that I know the prices the other dealer can offer, I am curious if the first two AD's can give me a better one?

Have you guys ever had an AD ask you for your serial.

 

This is general policy for Omega Boutiques and AD's alike. The reason why - they log into the extranet with the serial number, which gives them a full rundown of the parts and accessories that are compatible with your timepiece.
While it doesn't make that much sense for stuff like buckles, it makes all the world of sense for straps (especially now since the majority are starting to be manufactured with more fitted/curved lug ends), bracelets, links, bezels, crowns, etc.
I wouldn't feel too hesitant about giving the serial to an AD or OB. Now, if it's a grey or private seller that would be a different matter.

 

Its normal, they did the same when my Electric blue SMP needed a new clasp, plus they are so efficient that they dint even give out certificate for the warranty after a service, I asked why and they said no need its all on there system, just give an AD my serial no and thats all they need

 

It's an AD. Sometimes people give them random numbers or wrong references so the only way to make sure they are getting the part right is throught the serial unless you bring in the watch to them physically. You'd be surprised as the amount if wrong references I've been provided by prospective clients so I always ask for a photo