Lync OWA integration - changing Lync pool

Hello

we have an Exchange and Lync 2010 infrastructure, OWA Lync integration is already configured, we are deploying a new Lync 2013 infrastructure, so we will have new Lync 2013 FE pool and the 2010 pool will be decommissioned, everything else remains the same.
I would guess we that we to update Lync Pool FQDN on the Exchange CAS server.

Since everything else remains the same, is the following command sufficient:

Get-OwaVirtualDirectory | Set-OwaVirtualDirectory -InstantMessagingServerName <Lync Pool Name>

Or do we need to run the command with the certificate thumbprint, etc… as follows :

Get-OwaVirtualDirectory | Set-OwaVirtualDirectory  -InstantMessagingServerName <Lync pool name>  -InstantMessagingCertificateThumbprint <certificate thumbprint> -InstantMessagingEnabled $true -InstantMessagingType  “OCS”

Thanks for your help,

Luca