Hi Martronic,
Welcome to Sony Community!
PCG-51211L is actually just the chassis number. To get the exact model name, kindly check here. We're not quite sure if you can [still] purchase a case/chassis of your laptop but we suggest contacting Encompass for further assistance: https://sony.encompass.com/staticpages/Contact_Us.
Regards,
Vincent
If my post answers your question, please mark it as "Accept as Solution"