Can Lookout 6.2 save files in a format that can be used by older versions - i.e 5.1?
From 5.1 to 6.2 yes.
Afraid of that.... what about exporting objects such as screens/windows?
Can be done, have to use a text editor (notepad) and select the source from the LKS. If I remember correctly, there are some minor syntax changes. The compile will tell you.