The change log in those files is old.
This is the most recent I can find:
http://hellninjacommando.com/con3d/beta/readme.html and it says no temporal support.
Here is vlad59's thread about Convolution3D and AviSynth 2.5:
http://forum.doom9.org/showthread.php?s=&threadid=38281
It wants a progressive source. I think Bach is correct about the use of dgbob. I wonder if a more accurate way is to split the source by field, filter, then reassemble the fields. That would also be more difficult.