As you can see below, when I run the above mentioned commands on my lab box (running version 8.0.3-11), I do get values:
a) from snmp walk (using support account):
[support@vm-sflabga support]$ snmpwalk -v2c -m all -c local 127.0.0.1 .1.3.6.1.4.1.393.200.130.2.2.1.1
SYMANTEC-EMAIL-SECURITY::instanceIndex.1 = INTEGER: 1
SYMANTEC-EMAIL-SECURITY::instanceIndex.2 = INTEGER: 2
SYMANTEC-EMAIL-SECURITY::instanceIndex.3 = INTEGER: 3
SYMANTEC-EMAIL-SECURITY::instanceDescr.1 = STRING: delivery
SYMANTEC-EMAIL-SECURITY::instanceDescr.2 = STRING: inbound
SYMANTEC-EMAIL-SECURITY::instanceDescr.3 = STRING: outbound
SYMANTEC-EMAIL-SECURITY::connections.1 = Gauge32: 10
SYMANTEC-EMAIL-SECURITY::connections.2 = Gauge32: 10
SYMANTEC-EMAIL-SECURITY::connections.3 = Gauge32: 0
SYMANTEC-EMAIL-SECURITY::dataRate.1 = Gauge32: 2790
SYMANTEC-EMAIL-SECURITY::dataRate.2 = Gauge32: 1014
SYMANTEC-EMAIL-SECURITY::dataRate.3 = Gauge32: 0
SYMANTEC-EMAIL-SECURITY::deferredMessages.1 = Gauge32: 0
SYMANTEC-EMAIL-SECURITY::deferredMessages.2 = Gauge32: 0
SYMANTEC-EMAIL-SECURITY::deferredMessages.3 = Gauge32: 0
SYMANTEC-EMAIL-SECURITY::messageRate.1 = Gauge32: 5
SYMANTEC-EMAIL-SECURITY::messageRate.2 = Gauge32: 6
SYMANTEC-EMAIL-SECURITY::messageRate.3 = Gauge32: 0
SYMANTEC-EMAIL-SECURITY::queueSize.1 = Gauge32: 4
SYMANTEC-EMAIL-SECURITY::queueSize.2 = Gauge32: 1
SYMANTEC-EMAIL-SECURITY::queueSize.3 = Gauge32: 0
SYMANTEC-EMAIL-SECURITY::queuedMessages.1 = Gauge32: 17
SYMANTEC-EMAIL-SECURITY::queuedMessages.2 = Gauge32: 2
SYMANTEC-EMAIL-SECURITY::queuedMessages.3 = Gauge32: 0
b) from mta-stats command as admin:
vm-sflabga> mta-stats
delivery_connections: 10
delivery_data_rate: 2610 bytes/sec
delivery_deferred_msgs: 0
delivery_msg_rate: 5 msg/sec
delivery_queue_size: 3 KB
delivery_queued_msgs: 9
inbound_deferred_msgs: 0
inbound_listener_connections: 10
inbound_listener_data_rate: 1014 bytes/sec
inbound_listener_msg_rate: 6 msg/sec
inbound_queue_size: 0 KB
inbound_queued_msgs: 2
outbound_deferred_msgs: 0
outbound_listener_connections: 0
outbound_listener_data_rate: 0 bytes/sec
outbound_listener_msg_rate: 0 msg/sec
outbound_queue_size: 0 KB
outbound_queued_msgs: 0