Most of the sagas were written by Christan monks and yes they did edit jobs on all the sagas.The most blatant of these are in the sayings of Hávamál where some are very against magic and witchcraft which was a part of Norse life as every village had there magic user.As the local healer was more often also the village Vitki!
So if a saga seems to full of morals that seem more at home in the Christain faith that is why the saga was edited for the newly converted Heathens!