Barry, I've tried several guthook patterns, and not yet found one that performs any better than my old fashioned approach. As for the handle of the 158OT, as you have noticed, it is the same assembly part as the 152OT and 154OT. That handle design was a winner from the get-go back in late 1973. It just "feels right". As for the blade design...change for the sake of change? Did customers request a guthook version of the Sharpfinger/Drop Point Hunter design? I really don't know that answer. The 154OT was introduced close on the heels of the popular Sharpfinger in 1976. The 158OT was introduced in 1988, which was the swan-song for the 154OT, so the fact that it replaced the 154OT is pretty apparent. Like the Sharpfinger, the Guthook Skinner was kept in the lineup through 2004. I have one as a "type" in my collection, but all four bucks I have dressed this year found me going for my old faithful combo, the Sharpfinger and the larger trailing point 165OT Woodsman.
Michael