to best of my knowledge the original Malew register for that period is held by Manx Museum - certainly that for the late 17th C is there but in a fairly fragile state - however that actual register was filmed many years ago and is on microfilm at Museum. Looking at my own notes I have a record of looking at actual (ie the original 18th C reg) register for baptisms in period 1731 onwards - most registers of this period are mixed Bapts, marr + burials.

Don't be confused by the mormon films - these are of the 1911 official transcript (which is all Registry have) - they are an excellent transcript (I've found very very few errors when I've needed to check against the actual Parish reg) tho the IGI fouls up some 'extracted' records as the year headings are not always clear and some clerks squeezed in a bapt at end of one list which appears to be in one year when you don't see the sequence but is actually in the following year