Gr Grandfather's Shillelagh???

When my parents were alive this spikey old stick was always behind the door in the laundry room. I asked my mum about it once and she said "oh that's old grandfather's walking stick" - meaning her grandfather. Her grandfather emmigrated to Australia from Ireland in the 1850's. When mum passed away I nearly threw it out but something made me to keep it and it has languished in the back of a robe at my place for the last ten years.
Just recently on the internet I stumbled on a Irish site which had a description of a shillelagh and that they were often made of blackthorn? wood (from memory that is).
It made me think of this blackish old stick and wonder if it was a shillelagh and if it had come from Ireland with my great grandfather. Maybe he had made it himself in the style of a shillelagh when he was out here? I'd love to find out.
I thought some of our Irish blippers may be able to tell me if it looks like the real deal or not. It's rather battered and the wood is splitting in parts - but seeing it spent about 150years in the hot, dry west of Qld and then another ten years here on the coast I suppose that is to be expected.
Any opinions welcome...........