do you mean active/standby state?
i am running 11.x.
active unit
[root@ve11a:Active:In Sync] config snmpget -v2c -c public localhost F5-BIGIP-SYSTEM-MIB::sysCmFailoverStatusId.0
F5-BIGIP-SYSTEM-MIB::sysCmFailoverStatusId.0 = INTEGER: active(4)
[root@ve11a:Active:In Sync] config snmptranslate -On F5-BIGIP-SYSTEM-MIB::sysCmFailoverStatusId.0
.1.3.6.1.4.1.3375.2.1.14.3.1.0
standby unit
[root@ve11b:Standby:In Sync] config snmpget -v2c -c public localhost F5-BIGIP-SYSTEM-MIB::sysCmFailoverStatusId.0
F5-BIGIP-SYSTEM-MIB::sysCmFailoverStatusId.0 = INTEGER: standby(3)
[root@ve11b:Standby:In Sync] config snmptranslate -On F5-BIGIP-SYSTEM-MIB::sysCmFailoverStatusId.0
.1.3.6.1.4.1.3375.2.1.14.3.1.0