MM, look at here

You are ok.
I rent cars on weekly basis year over year, so you can take my words -

Alamo is a good company, just like Hertz and Avis. They are treating customers nicely, you will not be in trouble as only as you are not involved in any accidents. A small scratch is considered as a normal wear, and most likely, previous renters had already noticed that and notified them, so they should have a record in their system. So no worry.

As a side note, always stay away from Fox and Thrifty...