I don't know whether Leopard had it when I was running it. I just don't use more; less is just so much more powerful. Both man more and man less open the same manpage, which is that of less. If you look at the sizes of the files /usr/bin/more and /usr/bin/less, they are identical. The two binaries are identical as well.
"Unfortunately, my level is too low to comment on one of the other answers... so here's an out-of-line comment: On Leopard, both more and less can be found in /usr/bin, with the same file size, date, and length. Interestingly neither is a link to the other:
-rwxr-xr-x 2 root wheel 254288 May 31 2008 /usr/bin/less
-rwxr-xr-x 2 root wheel 254288 May 31 2008 /usr/bin/more
So I guess Snow Leopard is indeed different, I didn't add these."