That should be good no issues at all.
If you want to have Fax t.38 Im working with a customer to configure this.
According to MS they support T.38 in CCM 6.0 with 2007 SP1, anyways you will need HW IOS MTP or 6608 blade to support fax pass-through Caps 254.
We will support it till 7.0
That is for T.38 in regards your normal VM calls you should be good.