The Sonitus suite bundled with SONAR is DX format. Since there is no bridge for DX plug-ins, there are two versions bundled with SONAR, one for 32bit hosts and one for 64bit hosts. The version installed depends on the host installation. The Sonitus plug-ins sold separately are 32bit DX and VST plug-ins.
In the case of VST plug-ins, in current 64bit only installations, Cakewalk does mix some 32bit dlls with the 64bit dlls in the VSTPlugins directory, for example Perfect Space and Cakewalk Sound Center.
In SONAR the plug-in header provides some clues about the plug-in format. VST plug-ins in addition to the preset drop down on the left side of the header have a drop down in the center of the header to manage presets and plug-in options. As of X3, the VST drop down name has been changed to VST2 and VST3, reflecting the different formats. If the plug-in is bridged the standard VST header is only displayed when the plug-in UI is opened while the SHIFT key is held down. Then the standard VST header is in a separate window usually under the plug-in UI.