This is a (cracked) pre-1913 Regular frame. The rotary bolt, the top lever spindle, the safety and the cocking cams all require removal of wood, and the width of the vertical channel for the spindle is usually larger than necessary. It is fair to say the inadequate wood surface in contact with the action is a design deficiency
At some point Hunter Arms appears to have caught on and cut a thicker stock head; a 1936 Reg. frame
Left - 1921 16g FW frame vertical head strip thickness averages .085.
Right -1942 12g FW frame Field strips average .110 thickness.
That said, fit and finish was somewhat better with pre-1913 Smiths than post-1913, and 1930s-40s Smiths. Lots of pre-1913 Smiths out there without cracks.