Not Irish after all?

I bought a few pay-per-view credits and had a look at findmypast's armed forces birth indices... and I found my ancestor. James Carden (spelled Cardon in the index... close enough) was born in 1818 in Island Bridge (an area of Dublin, Ireland). I already knew he was born there around 1818 or 1819, but now at least I've got the exact year pinned down. Too bad if I want to find out more I have to spend a lot more money to do so. And I really wish these certificates were digitized so I could just view them; I don't really care if I have a paper copy in hand (in fact, I'd prefer not to).

This new information also points to the fact that James may not have been Irish at all. It looks like his father was probably a military man as well. Perhaps the family didn't even spend much time in Ireland. Unfortunately, the time period we're talking about is before 1841, so I can't even search the censuses to find out the whereabouts of this family.