My TAIC report says that
the A6M3 at 5,650lbs has a climb rate of
Rate @ SL = 2960 ft/min
Rate @ 19,700ft = 2640 ft/min
Time to 10k = 3.3 min
Time to 20k = 7.0 min
the A6M5 at 5,920 lbs has a climb rate of
Rate @ SL = 2800 ft/min
Rate @ 19,700ft = 2470 ft/min
Time to 10k = 3.4 min
Time to 20k = 7.4 min
But it doesn't have any data on the A6M2, except that its loaded weight was 5,400lbs. Plus, I'm not sure if this particular data sheet is from actual flight tests or estimates of performance.
But it certainly seems that the AH A6M2 is very close to this data and seems to be in the ballpark.