I wouldn't hold my breath to be honest although I have no personal experience.

It can be a drawn out process seeking discounts on high end watches anyway because the retailers are not meant to discount as part of their agreement with suppliers. It is possible but is more likely in a chain with a really empowered local manager. Also you tend to get a better discount on items in stock rather than items ordered in (which makes things a bit hit and miss at T5).

Why not buy the watch at your destination? The US can be a very good place to buy nice watches, especially if you can skip the sales tax by shipping out of state.