The article goes into details on why they believe this means people were around before the Clovis people arrived (or the locals developed or borrowed the design from the Clovis point)
nut it includes this factoid on Luminesence dating:
why is this important? Because if true, that means they didn't walk over the glaciers... implying that maybe folks just came down along the coast.
To establish their age, Wernecke and his colleagues submitted 18 of the artifacts to a lab for optically stimulated luminescence dating — a process that analyzes tiny grains in the soils to reveal when they were last exposed to sunlight, thereby giving a sense of how long they’ve been buried. The results showed that the artifacts were between 13,200 to 16,700 years old.