Quote:
The test administrator will provide you with scratch paper for use during the test. Scratch paper is not to be used before the test or during breaks. All paper, in its entirety, must be returned to the test center administrator at the end of the testing session. If you are observed using any document or paper other than the scratch paper given to you by test center staff, it will be confiscated. You may not bring your own paper and you may not remove any paper from the testing room at any time, or write on anything other than the paper provided (e.g., computer or workstation).
From here, you do have all the necessary information
https://www.ets.org/gre/revised_general/test_day/However, it does not describe if it is flat or less but I do not think it is not the real point. The point is if you are well prepared for the exam. The paper grided or not is almost irrelevant I guess.
Regards