Yeah sure the r600 is:
2.4GHz: 9.1dBi
5GHz: 8.6dBi
I dont have the r610 as we dont use it, we only use the r510 and r710.
Note: The r500 and the r510 are both 5dBi, so it's safe to say they are using the same antenna in the r610 as they are in the r600.
Hope this helps, and good luck with sorting out your MESH issue.
🙂