Yes, BA's first 5 A320s are series 100s. I still don't think BA would have had too much trouble finding a buyer for the aircraft, around the time of delivery. Being "very early build" machines doesn't really matter when the aircraft is 6 months old and it's the most advanced airliner flying!
I take your point about the A320-100 now though when they're 12 years old, I always wondered whether BA would strike a deal to sell 'em to Air France who already operate 12 A320-100s, maybe now they will once more V2500-powered A320s arrive.
In a similar vein, I doubt anyone will be falling over themselves to take the 2 non-ER B777-200s that BA have just returned to Boeing. They may have been of interest to Asian airlines like Cathay/Malaysian as range is not an issue on their trunk routes, but their GE90 engines mean these airlines are unlikely to be interested.
Only 2 potential customers spring to mind;
China Southern and JAL, who've switched from PW to GE for recent 777 orders.