According to the highly respected [WORMATLAS: A Database of Behavioral and Structural Anatomy of Caenorhabditis elegans](http://www.wormatlas.org/ver1/MoW_built0.92/nervous_system.html), the number is invariable in this animal, one of the most studied in the world.

The number of synapses are not, however.

>The full list of synapses for hermaphrodite (including larval stages) and adult male are currently being reviewed and revised for the Wormwiring Project. All data comes from re/analysis of the sections for the hermaphrodite N2U, N2T, N2W and JSE animals, and male N2Y and n930 animals. The total counts of both electrical and chemical synapses are likely to be substantially higher than what was reported in the Mind of a Worm. 

Would I be surprised if someone found a different number in a particular  specimen? No more so than when people are born with four kidneys, etc.