The stamps in your passport confirm the dates when you were registered with the GNIB. The GNIB may issue residence permissions, or merely confirm your registration on foot of a permission which has issued from the Minister for Justice. To see whether the permissions you hold amount to sufficient reckonable residency permission to entitle you to apply for naturalisation, go to the Department of Justice's helpful residency calculator, which is here: http://www.inis.gov.ie/en/inis/pages/naturalisation_residency_calculator
First, enter the dates that are marked in your passport, for example you might have a Stamp 1 from 10.01.2010 to 31.12.2010 marked in your passport. These should add up to five of the previous nine years, and to a full 365 days immediately prior to application.
If you don't have enough reckonable residency to apply on this basis, look again at the source of those permissions. So, if you had a work permit that stated that you had permission to work from 01.01.2010 to 31.12.2010, but the GNIB had marked the stamp on your passport on 10.01.2010, you can go back and correct the residency calculator so that the dates are counted from 01.01.2010.
The same applies to permission letters that issue from the Minister for Justice (through the Irish Naturalisation and Immigration Service). So, if you received a letter from the INIS to say you have been granted permission to reside and work on whatever conditions from 01.01.2010 to 31.12.2010, then you can enter those dates in the calculator - even if the stamp was marked on your passport a few days later.
If you find you are eligible to apply, print the calculator, and attach photocopies of the stamps in your Passport, as well as of the Work Permits or letters from the Minister on which you are relying, and send those with your application.