So, taking a clue from other posts, I went into the Startup Disk PrefPane and selected my internal drive then quit System Preferences and ran the Terminal command successfully.....
My Acc't$ bless --info --getboot
/dev/disk0s2
Perhaps having recently reset PRAM for another issue may have contributed to my earlier failure.....and until I ACTUALLY selected a startup disk in the PrefPane, there was nothing for the Terminal command to recover.
