I recall that it was originally in the Complete Book of Elves... not to disagree with you Sage. I haven't looked at my 2E books in a long time. I used to use the Archer kit, but never owned halflings and gnomes..
*** A Forgotten Realms Addict since 1990 *** Treasures of the Past, a Second Edition Play-by-Post game for and by Candlekeep Sages--http://www.rpol.net/game.cgi?gi=52011
The archer kit can be found both in the Complete book of Elves and the Complete Books of Gnomes and Halflings (still one of my favorite 2ed. books) under halfling.