Use the PC Master .las file without GCP's to produce Topo

I have a large project that is not dependent on correct georeferencing data to align the point cloud to GCP’s nor is it dependent on a colorized .las. Can I produce a Topo deliverable out of Rock using on PC Master .las without GCP’s?

You certainly can! It might be worth it to wait for an OPUS solution just in case you want to use the data later on for any kind of precision work. However it will most definitely provide a highly accurate topo even with the lower precision “default” values outputted from your RINEX file (aka the HEADER values).