No, it's Maxwell. There's not a mobile Pascal Quadro that'd work at that form factor and thermal capacity at this time. The Kaby Lake Dell XPS 15 (Precision 5520's sibling) uses a Pascal GTX, though.
Maxwell Quadro mobile parts end in "M" (in addition to starting with "M"), which leads me to believe that this is just a typo'd Pascal part.
Is the NVIDIA Quadro M1200 included in the Precision 5520 based on GP107-400 (GTX 1050 Ti) or GP107-300 (GTX 1050)?
[1]: http://www.dell.com/us/business/p/precision-15-5520-laptop/p...