Yes it does need to be disclosed and you may find that there are additional questions.... which may need even the Gardai in question to answer. It is appropriate and legitimate to ask that question worded in that way. I have to answer that question each year as well as a number of others that might cause consternation... and yes I actually do tell them that I have spoken to Gardai regularly on anti social behaviour and once for a background check confirmation that I lived peaceably in another country, and at the time I was going to be working runway side in an Airport so they wanted to check it was safe to let me work there. Interaction means any interaction. Most likely they will contact the Gardai ...give them your details and do check on that file, if it is even still available.