Can I just cut the bare aluminum conductor off in the SER cable where it comes out of the jacket and use the three insulated conductors (which are striped and labled) between the meter and the panelboard?
I'm not sure I can find a code reference, but I'd say it's a bad idea. One of the differences between SEU and SER is that SEU has the neutral wrapped around the phase conductors. This provides significant protection of that insulation. There would be less need for this protection in SER because it is meant to be used after an OCPD.