Needless to say that I'd strongly recommend to check the (first) 2.7 for leaks.

I don't know if this should be considered just as the recapping of older Macs; it's possible that all the LCS (at least the dual core models) start to leak at some point, so it would maybe be a good idea to overhaul it before it starts to leak. Waiting until the "PSU-boom" may take less effort, but the best is to preserve one more watercooled G5. Unfortunately this common problem was and will be the death reason for a considerable amount of these Macs.