Yes, that's really what I'm leaning towards. Other than a few reeds that require too much air to sound, it's in playable condition. I've bought a DVD for beginning concertina (the John Williams one from Homespun). I can follow along and use the same fingerings as he's using on the C/G and I can also transpose to what they would be on a G/D.
So anyway, having my concertina in Ab/Eb isn't going to stop me from learning tunes, and that's all I can really do right now anyway. It will be a while before I really have to worry about playing concertina in a session, and I could buy another concertina for that purpose if I get to that point and feel serious enough about playing with others.
Also, I do like the way it sounds. I think I'll keep it the way it is and learn to play it for now; I'm going to put off the restoration for a while and I don't want to make any decisions about re-tuning it until I know how to play it and know what I'd be losing if I go away from Ab/Eb. Maybe I'll like it better that way anyway, and besides, there's no hurry.
--Eric