Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

(Attachment Link)   Super nice example you have.
 I also have a fairly nice Bing like this that came with it's box and on the box is 10/120/3. I did some research back when I acquired it and did find an article or some reference to the 10/120 model number. 
 The box is a hard cardboard that is very wood like with heavy staples.

A very well preserved label on that box!  The label on mine fell off/disintegrated.

Thanks for posting the picture.

My reference to the 70/120 in the title of the thread came from the www.weedensteam.com website:

"Little is know about the history of this Bing engine, listed as either a 10/120 or 70/120.
Often mistaken for a Weeden No. 14, particullarily if the dark base with red pinstripes has been repainted. The groove in the flywheel and the shape of the cylinder are easy identifying features."