You will not have any problems. After you upload the project and restore it back to a project file, you will be able to go into the display settings and change the screen resolution. Depending if your PV600+ is black and white or color, if it is key or touch, you just select the new settings and configure the displays to suit the new PV1000+.
You may find that you want to go through the displays and move everything to make better use of the screen, but this is just drag and drop kind of stuff.
The tag structure, display logic, and everything stays the same.