Nothing seems to be cut-and-dry with RMKsl
(except the change in blade stamp in early 1966). Here is something I found that raises some interesting questions. I'll address them by editing this post later, adding my thoughts and opinions.
Those of you who are interested can have the fun of analyzing this picture in the context of this subject, and determining what some of those questions might be. It might also be a good exercise to develop a plausible story for this evidence, plus alternative explanations. We could then form an idea of what additional information we might seek to add weight to the explanation.
Regards, Jack