They use different plugin namespaces, so even though the code might “technically” be compatible (or might have been at some point) the plugins themselves need to be ported from one to the other.
From what I can see about gloobus-preview, it should work with either nautilus or nautilus-elementary, since they seem to both use the same plugin system. With access to the plugin source code, someone might be able to port it to work with caja. I’ve never used this plugin, but the code seems to be on https://launchpad.net/gloobus-preview (it looks pretty out of date, though)