Maybe the factory put your crank sprocket on backwards, and your dot is on other side?
Anything is possible with Triumph.
Look on the same page in manual, and you will see how to align the cam arrows at TDC. If your cams have never been touched, the arrows should align with top edge of case pointing towards each other at TDC
(stock cams only).
I would recommend that you double check it with a rod in #1 cylinder sparkplug hole, but that should be damed close. I can't recall about the key way... wouldn't trust it anyway.