Various drives have been delivered from C=, but I believe the Chinon FB-354 is the most common in both the A500 and the A3000.
If your A500 drive is indeed a Chinon FB-354, then all you need to do is move swap the eject button over, and stick it in.
As for the A2000 drive, yes you can hook it up to your A3000 and test it, don't worry, it won't blow up (well, it shouldn't...). Chances are this drive is a Chinon FB-354 as well... but it will work regardless of what brand it is.
-Paul
