If it's a server on which sendmail has been installed via a package manager, why not, at least as a first step, consult the package manager or its' installation database e.g. on a Solaris box,

grep ' f .*sendmail ' /var/sadm/install/contents
[download]

(the whitespace is important) ??

I know similar can be done on DRS, HP & Linux - but, not being as familiar with their package managers, I ought'nt provide too much detail (coz it'll probably be wrong and thus, at the very least, misleading)