For a clone, you'd have to go all-grain or partial mash. Elysian uses pumpkin in the mash, kettle, and primary.
I'm guessing 1.060 OG / 1.015 FG
Off of Elysian's website...
BODY
Light to Medium
TASTING NOTES
A very drinkable pumpkin ale—brewed with seven and a half pounds of pumpkin per barrel and spiced in conditioning with ginger, cinnamon, nutmeg, cloves and allspice. (so figure 2.5 lbs. total roasted pumpkin for a 5 gallon batch in the mash & boil)
MALTS
Pale, Munich, Crystal (likely C60)
HOPS
Lightly bittered with Magnum (0.33 oz. @ 45 min?)
SPECIAL
Both roasted and raw pumpkin seeds are in the mash, with pumpkin added to the mash, kettle and fermenter.
ABV: 5.9%
IBU: 18