It is possible that some models may have scratches.
You can tell which phones have scratches because all refurbished phones are divided into "grades" ranging from Excellent to Fair.
When the phone is in Excellent condition, it is very similar to a new Phone.
These are the grades:
Excellent: the item is in perfect condition and looks very much like a new item
Good: Small scratches can be seen, but nothing very visible
Fair: Used marks and scratches become more visible with a fair item