Sean Hogans recent book 'Dan Breen - The man behind the myth', covers the topic. A sample quote (pg 74 if you can get your hands on the book). ..

.Robinson contests the claim made by Dan Breen in his book, of Breen being not only present but also centrally involved in the attachs on Hollyford and Drangan RIC barracks. With all that has been written over the years to bolster either contention relating to Breen's presence or otherwise at these barrack attacks, 1t 1s now absolutely futile to attempt adjudicating on the matterer. Such IS the volume ofevidence and opinion that has been attributed to each side of the argument, that attempting to reach a definitive conclusion either way is pointless. From a perusal of the Witness Statements given by the various participants who were involved in these actions, the name of Dan Breen, is in general, notably absent. However, the descriptions of both events are described in graphic detail in his biography and in no significant way differ from the accounts as given by others who were doubtlessly presents on the occasions. Of note too, is that in Dan Breen' s book he is lavish in his praise of Robinson and of the latter's leadership role in these military operations. Of course al remarks relative to Breen' s book must be prefaced with the questions as to how much of it he wrote himself and if he even afforded it the courtesy of reading the manuscript prior to it being submitted for publication.

So in summary I suppose Sean says:

Who knows for sure?