Hello,
As long as the certificate is authentic it doesn't matter if it is laminated. So it is not an issue. But if you still think there might be an issue, then try contacting the college regarding this. 
Donot worry, it is not going to make a problem.
Good Luck!

Hello Shresha,

We understand you concern. Please note that most of the times there should be no problem in laminating your marks card after they have been signed my all the authorities as it is the best way to protect these important documents. If your college has a problem with that, just explain to them as it is impossibe to remove the lamination now. All the best!