I am confirming that you can upgrade the MacBook Pro 15” A1286 (Mid 2012) (Non-Retina) 1440x900 Glossy to a High Resolution (1860x1050) A1286 (2011) Display Assembly. You can get the Display Assembly on Ebay for roughly $150.
The process is not too difficult and you must do some minor tweaks. There is a small amount of excess plastic on both sides of pin connectors on the display data cable that you must shave off in order to fit into socket on logic board. (Try fitting the connector and you will see where the plastic impedes. Take a small razor blade and just ever so slightly shave off the excess plastic. (Be careful and take your time) When done properly the cable will then fit securely into socket. The metal arm that swings over and locks cable into place will not fit 100% as the two connections are just slightly different.
How to fix – Fully insert cable into socket, place piece of strong double sided tape on top of connectors, swing metal clip over on top of double sided tape. Press down firmly and this will secure both the metal clip and connector. The screen will show up as 1680x1050 native, I reinstalled macOS to make sure everything runs smooth. Just be precise, take your time, and this fix will work perfectly. This setup has been working for me for 6+ months. (I found re-aligning the display assembly to be the hardest part)
Cheers and hope this helps : ) CT
Use this guide as reference –
MacBook Pro 15" Unibody Mid 2012 Display Replacement