I don't think that the passenger areas at FP changed much at all from when I first used them in the late 1950s or early '60s until the changes resulting from building works in the last few years.
There were three pedestrian tunnels roughly in the shape of a T: the "cross bar" tunnels ended on Seven Sisters Road and Wells Terrace, while the "stem" ended on Station Place. The platforms were reached by pairs of staircases going down either side of the stem tunnel. Obviously the services from each platform except northbound Piccadilly changed during the conversion from Northern Line branch to Victoria Line.
There were (and are) spiral staircases between tube platform level and the BR / NR station above, but I don't think they've changed either. However I've rarely used them, I was normally changing between tubes and the Wells Terrace buses.
The bus numbers changed though: the 212 became the W7 and the 233 became the W3. I remember the originals when they were operated by RFs and RTs
.