Have a look at the Familysearch.org website for the LDS catalog for dates and films available to view.

Two are:
Title Parish register transcripts of St. Mary's Church (Castletown), 1807-1859.
Authors Church of England. St. Mary's Church (Castletown, Isle of Man) (Main Author)
Note Location
Film
Registry of Deeds, official copy, parish register of Castletown, baptisms, 1807-1859. FHL BRITISH Film 106714

Title Parish register transcripts, 1849-1883
Authors Church of England. St. Mary's Church (Castletown, Isle of Man) (Main Author)
Note Location
Film
Parish register transcripts FHL BRITISH Film 106193 Item 2

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