Antique Open Case Pocket Watch (Ingersoll?) Works But Needs TLC (No Chain)

I never wanted to know so much about pocket watches in my life! lol. this lil beauty kept me up hours passed my bedtime trying to research it! lol. And I still am not sure what I've got here other than its old, old & still ticks!. I'm not a watch expert by any means & this watch could be worth about $100 unless you pry off the back cover & discover its gold filled ($1000-$3,000 if so) & not a brass metal. In my studies I did learn that roman numerals were being put on pocket watches after the 1900's so this watch is most likely older than that or circa!. It has many signs of wear but that makes it cool! think of how many hands this has passed thru in the last 120years or more! The stories it must have to tell!lol.I did notice that the seconds hand has come loose & is kind of bouncing around inside the case even though the mechanics are still ticking away. if you know about watches, please teach me!?.lol.tell me what I have here?lol