I do not have anymore this generator for 1.5. Even for me...
Did you asked on joomla.org how to make usable a 1.6 component on 1.5 ?
For differences, I would say :
- Install manifest file
- MCV totally different.
- ACLs totally differents
- UI layer
- JDom will have lot of problems
My advice is to copy an existing component, or Joomla native one (content / contacts / or else)
and then to rewrite inside.
You can see how long it is without cook
I am a bit scared because I have also kept 3 clients with 1.5 and this is frightening ....