no just turn up - open 6 days a week 10am (on the dot!) to 5pm
If you want to look at many deeds then they are happy to take orders in advance and have them ready for the day - the library have many manuscript collections many of which contain family trees - however you can do much before you get here both to familiarise yourself with Manx records (the Museum Library is effectively the Manx national record office for pre 1900 material) - try www.manxnotebook.com, the Lawson minisite part of www.iomfhs.im
also bring a digital camera and a couple of memory sticks with you as digital scans and photos are free but if you want hard copies then these cost. Sort out your census entries as this is easily done off Island and all you get at Museum will be the microfiche and films using the same index as iomfhs site.
Just allow plenty of time - most of your family appear to be buried in Rushen - the Museum has copies of the transcribed MI's + plots of the yard - Rushen is not too difficult to reach by public transport - look up buses etc via www.gov.im - buying a multijourney ticket is a significant cost saver