I'd like to apply the following patch to flip the sense of the prefix
argument to interact calls to insert-register. I find the current
default behavior of putting point before the inserted text annoying; I
want it after more often and don't want to add C-u to an already long
key sequence.

Of course, this is an incompatible change to a very old interface, but
the breakage should be limited to muscle memory and recorded macros.

=== modified file 'lisp/register.el'
--- lisp/register.el	2014-06-03 09:06:18 +0000
+++ lisp/register.el	2014-09-11 02:24:53 +0000
@@ -425,13 +425,14 @@
   "Insert contents of register REGISTER.  (REGISTER is a character.)
 Normally puts point before and mark after the inserted text.
 If optional second arg is non-nil, puts mark before and point after.
-Interactively, second arg is non-nil if prefix arg is supplied.
+Interactively, second arg is nil if prefix arg is supplied and t
+otherwise.

 Interactively, reads the register using `register-read-with-preview'."
   (interactive (progn
 		 (barf-if-buffer-read-only)
 		 (list (register-read-with-preview "Insert register: ")
-		       current-prefix-arg)))
+		       (not current-prefix-arg))))
   (push-mark)
   (let ((val (get-register register)))
     (cond