So there's no firmware related stuff that would prevent it from being upgraded?? Or motherboard stuff?? 

The system isn't in warranty cuz I bought off ebay 

So they don't do any edid locks or locks to motherboard?? Do they all use 30 pin connectors?? 

Also see this

Do they have 1 and 2 lane edp connectors??
https://www.dell.com/community/en/conversations/inspiron/upgrade-screen-resolution-1366x768-to-full-hd-1920x1080-inspiron-5559/647f7884f4ccf8a8de694e15

ok talked to someone at parts people and they said it should be just a panel replacement for 2 part numbers they gave me

While it's possible, taking the system value into consideration prior to proceed with upgrade plan.  Contact Parts People and providing system tag to get a quote for FHD screen.  The labor is around $100 USD if users want to obtain installation service.

https://www.parts-people.com/index.php?action=category&id=142&subid=1445&refine=lcd+screen

Service manual for DIY  https://www.dell.com/support/manuals/en-us/precision-15-3550-laptop/precision_3550_sm/removing-display-panel?guid=guid-fa49eaa7-1647-4e6c-8ccd-fdbd6d16d5da&lang=en-us

Glad to hear the progress.  Remember to take final cost into consideration.