Q: Apple Store guy said I could swap my watch if s new one comes out in 40 days of purchase

Hi

You will need to talk to the store.

No-one here can assist you - this is a user-based technical support community.

Mike...

You can ask Apple directly on Twitter:   @AppleSupport

Here is information quoted directly from the Apple Store Sales Policy:

"Should Apple reduce its price on any Apple-branded product within 14 calendar days from the date you receive your product, feel free to visit an Apple Retail Store or contact the Apple Contact Center at 1-800-676-2775 to request a refund or credit of the difference between the price you were charged and the current selling price. To receive the refund or credit you must contact Apple within 14 calendar days of the price change. Please note that this excludes limited-time price reductions, such as those that occur during special sales events, such as Black Friday or Cyber Monday."

either you misheard what he said or he was not providing accurate information

http://www.apple.com/shop/help/returns_refund

fourteen might sound like forty, or if I say it in my native Brooklyn accent I could see how a NYC employee could be misheard speaking to a customer:

fortdeen (also : fort&!$#@%deen)

Apple does provide exceptions to this policy for the release of new products. As already advised they need to talk to someone from Apple to see what their policy is for the Watch.