I think, recalling conversations with late Noreen Cottier, that many if not all, of FHS transcripts were made from original doc - she told me that they took a portable photocopier to some churches as the vicar would not let them off the church premises - a few were not done in early day becauses the vicar would not allow copying.

Under a new Act of Tynwald (2001 I think)- Church Records Act - all records older than a certain date (pre 1900 ?) have to be deposited in Manx Museum so suspect no originals in churches - the Bishops transcripts are incomplete but some portions seem to turn up along with other documents so there is hope of finding more.