Not necessarily. The GN did have those in Railway and Tramway versions, one of the Tramway ones is in the IRRS library. Almost certainly Hill of Howth placed where public rights of way and tramway met.
The odd, to our eyes, wording probably borrows from 19th century legalese.
Original? Yes. Antique? Perhaps not.
If you've been wondering where all those IE bridgeplates that have "fallen off" went, look no further than South Dublin Auctions.