Was the clutch giving problems that suggested the plates were stuck? if so then you are probably best off stripping and checking. The clutch is supposedly balanced so best to mark the three heavy bits to make sure they go back the same way. Use a 2 or 3 G clamps to control the release of the springs and to compress for reassembly.
The engine speed clutches are prone to sticking if left for a long time and freeing them in situ brutally by slamming into gear can lead to damage, typically knocking a tooth of 1st gear. Best way is to try and start the bike in gear (you need a quiet straight road for this) and then rock the bike on the throttle. Normally frees it within a few yards.