I ran into a similar looking set of files after unpacking the installer.exe using 7zip.
My interest was not so much automating the install as learning how the installer was written (it contained some nice functionality I'd like to use in my own installers).
The main difference was that I had a file named . That file was also the largest file.
Using "strings /n 4 installer.exe" I managed to get some neat switches:
When renaming the "" to bulk.exe it turned out to have the versioninfo structure, and some more information was revealed merely by right-clicking it and selecting properties.
Running that file started the installer. However, 7zip refused to open it.
On a hunch I renamed it to bulk.msi and ran the dark.exe from the wix tool chain to reverse engineer it to source code. Interestingly that worked just fine!
However, it seems that either all the interesting stuff was done by an outer layer wrapper (some google searches indicated it was probably written using wise installer) or hidden from view by using custom actions.
All the best,