Columbia part 2

Eehm, think I've bought another Columbia (and still no Decca soundbox ).
Today's find is a Columbia model # 204. I got it directly from the original owners! So this is a real "second hand".

But as I still don't know too much about these nice Columbia portables, is there anyone who can tell me how to date the Columbia's and things like were the model's like 200,201,203, 204 etc. available at the same time or just one or two per year (like 1930 = 200 and 201 or 1934 =204 or so)
Are these also build well into the 1950's? And are the 100 series older than the 200 series etc etc.
A lot of questions but I hope that there's somebody who's got some anwers.
eng bo

hello,

i also have a columbia 204 but your seems to be a more expensive version! my seems a little plain by comparison ... i too have lots of questions , date? value ? cost when new and models etc.... but very few answers!

good luck