Hi guys!
I have been given to understand that the 'A' in A500K stands for Audio Taper (log) and that 'L' and 'B' refer to Linear Taper. Reverse-Audio Taper pots are usually marked 'C' (e.g. C1Meg). I have checked numerous sources about this and they agree unanimously.
Hope that helps a bit.
Peter
Thanks alot, it really helped me