We've taken this up in several other threads recently; if you do a search on the name of either ship you'll find some interesting material, including a link to an excellent comparative review of the kits on the Steel Navy website.
The bottom line is that the Kearsarge kit did indeed appear first - though the Alabama hit the shelves within a few months, both of them appearing near the start of the American Civil War Centennial in 1961. Was that really 45 years ago? Oh, my achin', post-middle-aged back. My parents gave me the Alabama for my eleventh birthday that year, and the Kearsarge for Christmas.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.