Is the right motherboard is in my Mac

My macbook pro mid 2012 was not on but was charging properly.I took for repair the guy said he will install a new software.A new software was installed and it was updated .When I went to pick up the mac he said still updating and can't take it.The next day he called me he told me the same issues with it.

He will look into it further.I left it there,I went to collect the mac after 1 week and it was completed dead.When I charged it,it won't charge it but instead blinking.I look on YouTube and notice its the battery connector so put the battery back but still not charging.

The guy was selling similar laptop after I took mine for repair.My concern he might took my motherboard off to put in his laptop and gave me his faulty.

How I'm gojng to find out is the right motherboard is in my Mac

Please help me out.

Thanks