If the spoiler provided by the dealer was new, they should provide the templates, or they should install the spoiler at no cost to you. Instructions come with the spoiler, they are not extra. Speak with the dealership owner; not the parts department personnel.
You can contact Toyota and request the two-piece template kit, Number TK-6620303.
Return the spoiler to the dealer for a refund. New PW, SR, and TCM spoilers are still widely available for sale; the others are not.
I did not use the templates for my install. Using the attached Scion spoiler document to extrapolate the measurements for the drilled holes locations, basic geometry makes the install easy. Also, SAE drill bits match close enough to the Metric bits.
Several site members did not drill holes and successfully used double sided tape. Proper hatch surface preparation and full spoiler tape coverage are essential. Product is 3M Scotch Mount Super Strength Molding Tape - Part Number 03614.