1985 til early 90's its not as detailed but.
400,500,600,some 700 Series are road (still same lower the number the lower level bike it was. except the 170 which was high...)
1000 series Aluminum Road
2000 series Carbon Road
800,900 series are MTB
700 Series can also be a multitrack, which is a 700c hybrid
after that you get into the thousands series stuff which can get confusing. or the new X.X (eg 1.2)
I feel like im missing stuff, i am in no way saying this is complete list just that after 85 there was some hierarchy also.