I'd go along with that except that most of the older log houses I've seen had squared logs. They also tended to be rather widely spaced, presumably to make the logs go further. I don't know what may have been used originally to chink the logs, possibly a mixture of mud and grass or hay and probably white-washed to make it more weather resistant. I don't think I've ever actually examined the chinking very carefully but these days, most look like they're chinked with cement. Very old log houses that have been abandoned for a long time tend the be missing the chinking and taking on the look of a corn crib. Usually the roof is of tin now.
The log house I lived had long been covered with siding on the outside but there were a few places on the inside where the logs could still be seen. I couldn't see the corner notches, so I don't know how those were made but I've really only seen a single type of corner notch on old log houses (and I don't know if it has a name, either). However, the logs on that house were much wider, maybe eight or ten inches wide, but I don't know how thick they were. It's actually possible they were sawn logs but the house was still constructed in a traditional log house manner. It's been fifty years since I've lived there and I don't remember what the finish of the logs was and probably took no note of it at the time. Log houses weren't that interesting at the time. The traditional way to square the logs was with a broad-axe, which usually leaves a distinctive pattern on the logs.