Position a rack in the center of the oven and preheat to 350 degrees F. Line 2 heavy large baking sheets with parchment paper.
In a medium bowl, combine the flour, oats, cinnamon, baking soda, salt and allspice. Stir to blend well. In a large bowl, combine the sugar, pumpkin puree, oil, syrup and vanilla; whisk to blend. Using a flexible rubber spatula, gradually stir the dry ingredients into the pumpkin mixture. Stir in the raisins.
For each cookie, drop 1 generous tablespoon of batter onto the prepared baking sheet, spacing the mounds about 1 inch apart (or use a mini ice cream scoop). Using moistened fingertips, flatten each to a 2-inch-diameter round. Sprinkle each cookie with a bit more raw sugar.
Bake the cookies until brown and a bit firm to the touch, 17 to 20 minutes. Using a metal spatula, transfer the cookies to a rack and cool completely.