No.
These muppets surface occasionally to carry out these acts of token terrorism.....they did so before Brexit even existed, they will do so even if Brexit was binned in the morning.
I suspect this bomb was more symbolic than owt else.....it was exploded almost on the day of the centenary of what the Republic calls the “War of Independence”, when Dan Breen and Sean Treacey et al bushwhacked and killed two coppers in a place called Soloheadbeg in Tipp thus launching the Troubles in the early post WW1 years which eventually resulted in Partition, a Civil War in the South, isolation for the Catholics in the North and which still resonates today in the Brexit stalemate....
(though to be fair, I may be crediting the culprits with too much grasp of Irish history here.....they might not have even ever heard of Soloheadbeg

)