[plt-scheme] archival docs on arity

Are there archival copies of PLT's documentation available somewhere on 
the web?

I'm looking for the earliest possible incarnation of this (1998 via the 
way back machine):

http://web.archive.org/web/19981206062856/www.cs.rice.edu/CS/PLT/packages/doc/mzscheme/node34.htm

I know that this interface was supported as early as May 1996, but I 
can't track down a working link to documentation.

http://groups.csail.mit.edu/mac/ftpdir/scheme-mail/HTML/rrrs-1996/msg00151.html

(This is not the most important historical inquiry so please don't 
expend a great deal of effort trying to track it down and/or make all 
the 1996 documentation available online.  A simple "no" will do.)

Does anyone remember if this API is inspired by other Schemes, or is 
this a PLT original?  I know case-lambda goes back to Dybvig and Hieb, 
LFP, July 1998 and Lisp and Symbolic Computation, September 1990, but 
those papers don't mention arity inspection and Chez doesn't include the 
PLT interface (although it appears definable).

Thanks,
David