Yes at the time of admission it can create problems in spelling errors it is mentioned in the gujcet hall ticket also

It is mandatory because during document verification and while taking your examination, incase they verify your details with any of the government photo ID, you might face complications.

So it will be better if your drop a mail to the exam conducting authority with all the relevant details.

Put subject line of the mail as "Error in admit card details - application number/registration number"