I set up the original CDN$ Amex account with no intention of using it for purchases; I only wanted to use it as a conduit to get a US$ card. So I didn't accumulate any points.

When I transfered the account to a US$ account, I got a new account number and everything. I am guessing that if I had had points in my account at the time of the transfer, they would have been converted using the current exchange rate. HOWEVER, my credit limit was converted 1:1 so you never know!