I would recommend downloading the Flex 3.2 compiled source code to a location at a folder parallel to your existing 3.1 application. I would then just try to copy the main config file from 3.1 to the 3.2 folder where it would overwrite the default 3.2 version. I would then copy the individual widget config files from the 3.1 to the 3.2 folder where it would also overwrite the default 3.2 version. There is no guarantee that this will work, but if it does it would require just a few minutes of work.
If the individual widgets do your work, you may need to compare what changed in the config files and try to figure what (hopefully minor) changes would be needed. You might also need to modify the main config file as there might be changes there as well.
Just an FYI, Flex Build 3.3 was released yesterday so this might have an impact on your upgrade plans.
