The Rock Island s/n 64145 has a RIA 3-07 dated barrel, note the square left side of the slide
which appears to be a carry-over from the early slide. The back of the leaf is also without
the top rib.

The Springfield s/n is 160963 with a SA 2-07 dated barrel, it has the common slide with the
round corners. DSCN2244.jpg