Unix-Agent - Postfix not detected

Set up Unix-agent for Postfix as per documentation http://www.observium.org/docs/apps/#postfix-mailgraph

Can successfully connect via telnet and output shows:

{{ *ommitted*
[postfix_mailq] => string(19) "Mail queue is empty"
[local] => string(0) ""
)
}}

Run running the Unix Agent poll, the log shows:

{{No include:
No include: Observium
No include: df
No include: mounts
No include: ps
No include: mem
No include: cpu
No include: uptime
No include: netif
No include: lnx_if:sep(58)
No include: tcp_conn_stats
No include: md
No include: diskstat
No include: kernel
No include: netctr
No include: postfix_mailq
No include: local}}

Am I interpreting this correctly as the Unix Agent reporting that there was no Postfix data in the Agent dump?