So I finally went ahead and got Object Desktop Manager because I've been wanting to try a few of Stardock's other apps after falling in love with Fences.
Everything has installed fine, including SpaceMonger 3 but when I open ODM SpaceMonger 3 shows up under the "Select software to install" category, listed as v3.00 with a 7mb download. Highlighting this and clicking "install" simply opens SM3 and ODM says it was updated successfully.
When I check the info on SpaceMonger it says it is indeed v3.0 build 1699...but when I reopen ODM it still shows up under "select software to install" (and it doesn't show up under my "Installed" tab)
It's not a huge deal as SpaceMonger 3 seems to be installed and working fine. It's just a minor annoyance and if there's an easy fix I'll take it. Thanks in advance for any pointers on this.