Seb,
Meaning of trim-code on FB/EK is identical to FE/FC (see
here.)
514 is external colour (or combination if appropriate, not in your case)
800 is internal trim colour(s)
Subsequent paint number(s) then provide the paint type(s) and BALM number(s).
Interesting that one of the sites you've come across lists the FB as being released in 1959. This is when it was
supposed to be released ("FB" = "59" in the GM-H model code), but it wasn't actually released until January 1960.
As far as date of manufacture is concerned, I think you'll need to find the FB-EK equivalent of Guru Ken to ascertain that. Generally, the chassis and engine numbers will help you to roughly identify the date of assembly. The ID plate number can be used to determine date of manufacture, but this is done somewhat empirically, requiring the collation of many ID tags such as Ken has done to be able to generate trend-lines.
Hope that helps,
RET