You can technically have more than a thousand though. If you put a decal in a favorites folder, you can delete it from the main collection list to make room and still have it available in the favorites folder.
There's also apparently a limit on the number of saved liveries you can have in the livery editor. I started getting "Save Failed" when trying to save liveries (cars, helmets and suits), and deleting liveries that I was finished with was the only thing that solved the problem. There's no counter or anything that I can find in the livery editor, so I have no idea what the limit is, or how many saved liveries I have.
