question

[aaa]

what exactly was the role of the producer for these reggae records? did they just organize it's arrangement and release, or were they involved creatively?

[Bellyman]

To answer your question in all would really mean to tell the story of reggae music. That has been done in excellence in some books that I can recommmend if you really want to understand the role that producers had and still have in shaping the music.
To put it the simple way, a producer is the man with the money. He pays the musicians/singers/engineers and owns the music that was created. There were/are producers who really created music like Lee Perry, Coxsone Dodd, Duke Reid, Prince Buster, King Tubby etc. and there were/are producers who had no or only little artistic influences.
For further reading :
David Katz - "Solid Foundation"
David Katz - "People funny Boy/The genius of Lee 'Scratch' Perry"
Steve Barrow & Peter Dalton - "The Rough Guide to Reggae"

[slimroy]

also check out bass culture. its not the best book but still a great read

[B B J]

"bass culture. its not the best book"

True