Is there a difference in the GTK themes depending on the system setup? It's just that I noticed the image posted by Dragynn is a different theme to mine - I'm running Openbox, see below.
*snip*
If that is the case, that the look of Hammer is dependent on the default settings on a system, is there a way that we can standardize the look?
I'm using an openbox theme that I created. I can switch themes easily by opening lxdecc and choosing Configure Openbox. I like that ability.

A "standardized look" is okay only if people are not required to use it. However, getting a standardized look across all versions of PCLinuxOS that would work well would be very difficult. Each version uses its own themes and has a different look. Having hammer use the system theme means that it will blend in with any of the various DEs in use on any of the remasters. In that way, it could be said to be standardized.