Well, I did indeed discover that I had made a mistake with those two replacement files. True, I had unzipped them, but they didn't end up where I thought they were. Consequently, my previous spidering was with the wrong files.
However, letting the spider run its course with the correct 1.8.1 files, I still only have 1264 pages spidered, which is about 200 or so pages short of what I end up with for 1.8.0. I have no idea why.
