1586 s is the highest 243/38 known, it is an rc, but it has plenty of rifles nearby to give it status of high that year, - though yours would be the highest now. Vol.I might have a higher rifle known, might check it, but the highest confirmed I have noted is this 1586 s
BTW, nothing is wrong with Bob Jensen's early articles, Peter Kuck did a good job updating them, but one must remember these were originally written before Backbone (late 80's early 90's), - collectors really should try and get these new books Mike & Bruce are developing, they are not only the best understanding that can be had with the current information available, but also rely heavily on Jon Speed's archive and research, each book is full of original documents.
You really can't rely upon any other book unless you are very specialized and or do your own research, which is very time consuming and of dubious value in time & energy involved.