Hello David,

The IGI has:
Anne Taggart
Isle of Man, Births and Baptisms, 1821-1911
christening: 23 May 1828 Arbory
parents: Paul Taggart, Eleanor Quayle

Mary Taggart
Isle of Man, Births and Baptisms, 1821-1911
christening: 30 Nov 1829 Arbory
parents: Paul Taggart, Eleanor Quayle

Paul Taggart
Isle of Man, Births and Baptisms, 1821-1911
christening: 03 Dec 1815 Malew
parents: Paul Taggart, Elinor Quayle

Isabella Taggyrt
Isle of Man, Births and Baptisms, 1821-1911
christening: 13 Aug 1820 Malew
parents: Paul Taggyrt, Eleanor Quayle

Thos Taggyrt
Isle of Man, Births and Baptisms, 1821-1911
christening: 08 Jun 1817 Malew
parents: Paul Taggyrt, Elizth Elenor Quayle

Cathe Taggyrt
Isle of Man, Births and Baptisms, 1821-1911
christening: 24 Nov 1822 Malew
parents: Paul Taggyrt, Elinor Quayle

[www.familysearch.org/search/collection/show#uri=ht tp://www.familysearch.org/searchapi/search/collection/1708663]
[Close the gap in ht tp in the middle of the URL.]

Your Thomas may have taken a few years off his age as he got older, as many people did. Death certs are often unreliable, depending on who filled them in.
A bapt in June would be spot-on for his age at death as given in the cert when relatives would be likely to know the date of his birthday, even if he was actually 63 (and 12 weeks). I think it is the correct bapt for him - Castletown is within Malew parish.

Sue