Oxygen, bugs, and moisture are the three things that will ruin grain in short order. If you had the grains stored airtight and moisture free, and don't show any visible signs of turning, they are probably fine.
HOWEVER, I certainly would repurpose those particular grains for another brew, and NOT use them in a Pliny Clone. The grains are certainly NOT at peak freshness after two months in the garage, and I wouldn't want to waste a metric s**tton of hops with subpar grain. Go buy fresh grain for the Pliny Clone, make something else with the old grain.