I don't believe there are any specs for sping compression at least I have not seen any. The only thing I have seen is that is that they should all be about the same.
You can set up a crude test with a drill press and bathroom scales. Set the drill press so you can compress the springs a set distance, maybe a half inch. Put each spring on the scales and compress each one the same distance and record the pounds required to compress this distance. You should be able to identify any weak springs.