MacBook Pro 15" Retina Display Mid 2012 Teardown - iFixit
Adamanta 16GB (2x8GB) Apple Memory Upgrade DDR3L 1600MHz SODIMM Compatible for iMac (Mid 2011, Late 2012, Early/Late 2013, Late 2014, Mid 2015), MacBook Pro (Early/Late 2011, Mid 2012), Mac Mini at Amazon.com
Apple MacBook Pro 13” Catalina 1TB SSHD 16GB RAM 2.5GHz i5 Non-Retina macOS 2012 719534711145 | eBay
Sold: 15-inch MacBook Pro Retina Mid-2012 // $1,095 - Denver Mac Repair
16 GB RAM Upgrade on MacBook Pro 15" (mid 2012) NON Retina - YouTube