Whirlpool gas cooktop cannot be replaced

I purchased a cooktop for my whirlpool gas range and was told by an appliance installer that my model will not allow the cooktop to be replaced. Would like to know if this is true or directions on how it can be done.

In order to replace the cooktop you have to remove all burners. Sometime it’s very hard to do it because the screws holding them becoming rusted in and it’s almost impossible to unscrew them.

Here are the breakdown diagrams and Replacement parts for WHIRLPOOL GS395LEGQ5 | AppliancePartsPros.com

Gene.