class Rails::Application

def asset_precompiled?(logical_path)

isn't precompiled and hence won't be available in production.
Called from asset helpers to alert you if you reference an asset URL that 
def asset_precompiled?(logical_path)
  if precompiled_assets.include?(logical_path)
    true
  elsif !config.cache_classes
    # Check to see if precompile list has been updated
    precompiled_assets(true).include?(logical_path)
  else
    false
  end
end