Steam Engine--salesman's sample, or model for show room.......100 + years old !!!

I have rescently purchased this item from a friend who had it for 25 years, and before he/she bought it, the previous owner had it for over 50 years !!!!!  I don't know exactly what it is, and where it may have come from !!  I had taken it to a show where people had their "hit and miss" engine's on display, and approx. 10 people looked at this and loved it, and of course they wanted to buy it !!  The thing all of the people were saying is that they thought is was more than 100 years old, dating it back to 1900 to 1920 !!  They had also stated they thought it was either a display piece or a salesman's sample !!  Any information could and would be helpful and kept as new knowledge !!  Thank you all so much !!