ᐅ Are roofing materials required for prefabricated garages? Is weather protection adequate?

We purchased a single prefabricated garage from Dahmit through the general contractor. My question is: Does the garage roof need a layer of gravel applied (for protection against, for example, UV radiation), or is the garage roof already adequately protected against weather conditions?
If some kind of protection, such as gravel, is necessary, can it be applied directly, or does a membrane need to be installed on the roof first?
What are your opinions and experiences?
Thank you

No, it is not necessary.

Leave it as is. Don't try to fix what isn't broken.