No - they're not there.
Here's the list:
http://www.vivre-a-niort.com/fr/dernieres-infos/2452/index.html
There's a good reason they're not there: they weren't arrested in Deux-Sevres. The monument is for those who were arrested in Deux-Sevres. They had been living in Niort, Deux-Sevres in 1941 and 1942 but seem to have fled, only to be picked up somewhere else in France, sometime in 1943.
Perhaps there are records somewhere else in France which details where and how they were arrested. All that Jean-Marie Pouplain states in his book is that they, along with a list of others, left Deux-Sevres secretly ('quittés clandestinement')
