Whoa there, cowboy. Assuming the German lab tech they used wasn't an actor what he did was conclude that the cross was made from lead that came from a certain region. From a lead mine in that region. A lead mine that has been in operation how long? How many tons of ingots shipped to where and when? It could have come from that mine 10 years ago and would still test the same. It could have been lead ballast that came to Nova Scotia with a Portugese fishing ship and someone in Nova Scotia re-melted it to make that cross. There is no proof of a Templar connection and no time lock. Lead has been lead and unchanged (it's a very stable element) since it was formed in stars and ended up in the spiral that eventually formed our planet. Billions of years ago. The impurities with it are what help localize it.
I didn't watch the video, but do they mention "voltammetry"? That's about the only way to age a lead object based on the lead oxide and lead dioxide on the surface since it was melted and cast (or recast). And that assumes it hasn't been relocated to different soil or conditions. If not, then I'd be curioius how it was dated.