be aware that the crankcase pumps up to only about 6 psi or so .. when testing seals use a hand pump and keep the pressure low or you'll blow a seal that may have been good.
i deal with pneumatic and hydraulic cylinders.. the seals may get "brittle" and not seal, but the seal still feels flexible. Sometimes they are so brittle they crack when bent.. Sometimes an aparently brittle seal seals just fine. I think it's a matter of the neoprene losing some of it's chemistry over a period of a year or years of non-use.
the only worthwhile observation is whether there's a leak or no leak.