If you have a close enough view you can spot the difference in the Lewis Action guns from the later swinging hammer guns at a glance.
Just look at the placement of the two cross pins in the rear of the frame. On the Lewis actions the rear (Sear) pin is higher than the front (hammer & cocking lever) pin, as on this Ranger. On the swinging hammer guns the rear pin is lower than the front one.
I learned this from Russ, had never noticed until he mentioned it.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra