It depends on what version of apache (httpd) your server is running.
(for example on redhat check using "rpm -q httpd" )
webwork.apache-config.dist is for apache/httpd version 1.x
webwork.apache2-config.dist is for apache/httpd version 2.x with x<4
webwork.apache2.4-config.dist is for apache/httpd version 2.4
The correct one should be copied into the file with name without ".dist"
It is nice to follow the correct naming of the files, although ultimately it should not matter, because you have to create a link to it from the /etc/httpd/conf.d directory, for example
webwork.conf -> /opt/webwork/webwork2/conf/webwork.apache2-config