Internally it is facially similar to a Smith & Wesson single action, but with differences.  The most obvious difference is the spring that applies pressure to the hand--it's very lightweight and goes around the axis of the hammer as opposed to the stiff spring that is inlet into the face of a Smith & Wesson hammer and pinned in place.

Tin cans and playing cards were both common. Also, bottles were plentiful.
Oh, and I do remember that poker chips could be used.

Tascosa at Fort Polk in 1968 I was issued a 36 tall, and it was to big.

The cylinder pin has a long spring inset into the side and a ribbed end to give you a good grip--you just squeeze it and pull.  I'm not sure how durable it would be with hard use over time, but this one still works well after 140 years, so maybe it was a good idea.

The three sideplate screws are all different lengths and not interchangeable--I mean the short screws will go into the longer holes, but the longer screws won't go into the shorter holes.  Non-interchangeable screws seems like a silly idea, but F&H wasn't the only company doing it that way.

Rack numbers maybe?