Hello,

Since you have filled all the details that are necessary, I don't think there will be any issue. Most of the students either due to stress or hurry tend to forget filling the date and the year on the exam sheet. It's very common and examiners get tons of sheets of such students. Since your sheet will obviously be among other people, it won't be as such issue because the examination was held on a particular date and sometimes when invigilators check the details part of paper after collecting them, they tend to correct if anything is wrong.

Hope this helps,

Thank you