Help Dating Johnson Chair Co. Desk Chair

I recently purchased this chair believing it to be from the 40's or 50's but I'm totally new to all this so I'm not really sure how to find out more information.

The maker was easily identifiable as Johnson Chair Co. but I'm not sure how I can find out more information as to when and where it was made.

There is a number stamped on the back of the chair reading 18629. I'm not sure if this is a serial number or possibly even a date stamp?

Any insight would be greatly appreciated.

 

Probably made pretty much the same for a lot of years. That said, I think yours probably from the 20s, on up to the WWII era. Number looks like an inventory number to me.

 

Google it
https://www.google.com/search?client=firefox-b-d&q=johnson+chair+co+office+chair