Thanks for that advice FD. Another fellow has advised me of that issue as well. I have a K75 base and bag in addition to the one I just purchased. Before I bought the new bag it was shown mounted on a K100RS, so I never thought to question if it was the K75/K100 base. Not until I tried fitting it to my bike did I discover that it was a K1/K1100 base. The new bag does fit my original base, as well as the K1/K1100 base it came with.
I hate to part with the new bag as it is in excellent condition - pretty much like new.
Both my K75 and the K1 base have RIES loop style zippers - in your experience is this not enough to ensure that a base will fit, or are there different RIES zippers involved?