Hi @vancej ...
There isn't a way to update all your assignment points on one screen. However, you can update all your due dates on one screen. Check out this Guide:
@James Jones has written a script that would allow you to change the points of assignments via a spreadsheet connected to your course. You can find the entire write-up here:
Hopefully these links will be of some help to you. Sing out if you have any questions...or post your questions to James' blog if you have specific questions for him.