If you are looking for one of these, then consider the later versions which came out from 1977 onwards.
1977 onwards serial number 525001-
08/81 onwards serial number 700001-
The earlier versions had nine elements in 7 groups, these have 9 elements in 9 groups. Apparently the difference after the change, was that the vignetting was less with these later versions.
All of the 24mm Nikkor lenses have floating elements, which is possibly the main reason they are so good close-up.
Source:- Nikon Compendium by Hillebrand and Hauschild, first English edition 1993.
The 24mm Nikkors seem to be on the rise price wise, even in these financially constrained times.
Mick.