Yeah they do get upgraded.

Do Potm cards upgrade OTW?

A: OTW items will be upgraded based on TOTW (until the end of the 2018-19 season), MOTM, Hero, Record Breaker and Team Of The Tournament selections. OTW items will NOT be upgraded based on POTM, Award Winner, SBC, or other in game event selection.

How does Potm work FIFA?

The POTM is chosen based on his real world performance during matches. Once revealed, play POTM Tournament to get POTM Points. Points will carry over each month. When you get enough POTM Points, use it to claim a POTM Player.