I just installed Photoshop CS6 and do not see "Working RGB-Adobe RGB (1998)" as an option any longer in the printer profile list. Why is it no longer there? I have approx 75-100 art images that I print giclee' images from that use this profile. I have tried using the profiles for the paper I use, but since the images were processed using the RGB profile, my new print-outs look lousy when compared to the old RGB profile.
Something is wrong with your installation. I can assure that I see Adobe RGB (1988) in the printer list in my installation of CS6, Photoshop 13.0.6 on my Mac running OS X Lion 10.7.5, though I would never use it as a printer profile.
You might need to re-examine your workflow and your color management. One should not use a device-independent color space like "Adobe RGB (1998)" as a printer profile.
Use only the specific device-dependent ICC printer profile for the combination of ink, paper and printer model you work with.
what station-two wrote
your Source Document Profile should be Adobe RGB (1998) if that is what you are using
your Printer Profile should be your SPECIFIC printer/paper/ink ICC profile
PHOTOSHOP MANAGES COLORS workflow for more info...