SQL 2008 R2 / Applying SP2 to ONE instance?

Hi there,

We have a 2 Node SQL Cluster with 5 existing instances on it (all patched to SP2).  Earlier in the week I installed another instance onto the cluster, but failed to realise that the ISO was just the RTM version.

Am I OK to just go and re apply the Service Packs to the nodes, or they anything special I should be aware of now that the SQL instances are at different patch levels?

Cheers