I'm not sure it is plausible. Poland was much more interested in Western Prussia, for several reasons.
- it used to belong to Poland (well, most of it)
- most of the main towns of the Prussian Confederation were in Western Prussia (Prussian Confederation was an alliance of Prussian burgers and knights who rebelled against the Teutonic Order and wanted to join Poland; they actually initiated the Thirteen Years War).
- Danzig was a very attractive seaport with it being at the mouth of Vistula as a bonus - Vistula river was an important route for Polish commerce.
- Western Prussia was richer, I think, with such towns like Danzig (Gdańsk), Thorn (Toruń), Kulm (Chełmno) and Elbing (Elbląg).
- I think there were more Poles or Kashubians in Western Prussia, although I doubt the ethnic reasaons were particularly valid at the time.