Uwe wrote:

1. It's a 1954 Smith-Corona Skyriter. And green keys are fairly common (a few of my Skyriters have green keys).
​2. One of the two spools should be driven automatically with each keystroke. There are a number of reasons why this might not be happening, so I'd suggest starting a new thread for that issue in the Maintenance sub-forum. 

Thank you!
I had seen quite a few like the image of yours you posted (very cool by the way) with the slightly different shade of green alternate keys. I just couldn't seem to find any that had all the same color keys.

I watched a few youtube videos and several people said the older skyriters had to have the spools manually turned. Do all models of the skyriter automatically advance the ribbon?

Thanks again

A typewriter would be fairly useless if you had to turn a spool - which happens to be located under a cover - every time you type a few characters. It would be great if you could provide links to these videos, I'm sure the comments made in them will prove to be very entertaining. V e - turn spool - r y - turn spool - e n t - turn spool - e r t - turn spool - a i - turn spool - n i n g - turn spool -  i n - turn spool - d e e - turn spool - d ! 

​As for the green keys, Skyriters made from '49 to '53 had two-tone green keys, models from '54 on (like the one below) used all the same colour green keys. Trust me, very common.