So I am making good progress over here.  This behavior may or may not be normal:
 
A 32 bit plugin that shows up in the manager utility (in 64 bit X3) can't be found when opening a project that contains said plugin.  
I tried wrapping it with jbridge and it still didn't find it.
 
If plugin manager shows it installed, why wont 64bit X3 open it?
 
 

If the Manager is referencing the 64bit plug but the plugin in that project is 32bit then they are, by definition, not the same plug. If this is true then I would guess that the referenced 32bit plugin in the project is referenced incorrectly or perhaps it has been removed from your system.
 
Just a guess.
 
Regards,

i believe that both the plug referenced in the manager and the one used inthe project are 32 bit.   But i will check on that to be sure.
JW

You need to specify the plug-in. Some older plug-ins, like DreamStation DXi and the Power FX plug-ins, won't work with a 64-bit Windows OS and likely never will.
 
If that's not the issue, reset and re-scan the plug-ins if you haven't done that since installing X3.