My father was Unit Historian of the 1st Engineer Special Brigade Association from around 1978 until he passed away in 2002. About 2005, I decided to try to determine if the Association still existed; I looked up all the officers; they had all passed away, or letters to them were returned to sender. I did receive a notice of a 2003 Reunion (in St Paul, as I recall). These talks about more recent ones:
http://www.myguidon.com/index.php?option=com_content&task=view&id=7529
http://www.longshoresoldiers.com/2011/09/wwii-port-company-reunions.html
that I was unaware of, but have no contacts listed. So, I have to conclude there is no group left, although you can call someone at the Engineer Museum at Fort Leonard Wood to see if they know.
If you are still registered and have any specific questions, please post them and I'll try to answer them. I have unit rosters and some other information on casualties from my father, as well as unit history information. Thank you!