"Older" ASM guns rarely need springs changed to make them reliable, that started when AWA bought into ASM and started using lightened mainsprings to give them that oft touted "Factory Action" job.....problem was the springs were too light for reliable ignition.
I have a pair of ASM's made for EMF that I've had over 10 years and never done anything to them, though I'm thinking of working over the actions and using Wolff springs, just to make them 'feel
' better.
If it's in good shape, and you like it, get it and shoot it at least 200 rounds before you decide it 'needs' anything. In that amount of shooting you'll be able to identify any probelm areas if they exist.