Well listening to the lyrics, it it makes reference to the Strike and Lockout in Dublin 1913/1914 Joe, and it does sound like it also refers to the Easter Rising

Have a read of this
http://multitext.ucc.ie/d/Dublin_1913Strike_and_Lockout

And I think this has a bearing on the song
The meeting was duly held in Liberty Hall, and amongst those present were:- Jim Connolly, Countess Markievicz, W. Partridge, P. T. Daly. Captain White presided, and Sean 0 Cathasaigh acted as secretary to the meeting. The proposed Constitution was the item principally discussed, and its formulas were generally approved of and tentatively accepted. On the motion of Jim Connolly, seconded by P. T. Daly, it was unanimously decided to hold a public meeting in the Concert Room, Liberty Hall, on March 22nd, 1914, to invite the workers of Dublin to attend, and to ask Jim Larkin to preside over the meeting, as it was felt by all that the Chief of the Labour movement should know all that was recommended before it was finally approved of.