I have made my own "labels" for them, as normal 4, thin 4 and bold 4. I have found no record of this, so it might be due to wares or other.
Anyhow, please let me know if you think this might be somehing or not. Sorry for the bad quality.
Normal 4



Thin 4
wider gap than the normal 4.Thick 4
no gap at allOther varieties?

smaller gap than normal 4?
unsure if this is a double 4 or not.Please let me know what you think. And again, I'm sorry for the quality of the pictures. All I have is my cellphone's camera.