I highly doubt it.
Tbh, I don't want to see a 13in RMBP.
15in is enough.
Retina on a 13in wouldn't be able to tell the difference between 2012 model.
The screen size is way to small for the resolution.
I think you're assuming the resolution will also be 2880x1800 on the 13".. Which it probably won't be. Apple has always aimed for the same DPI across different sizes, not the same resolutions.
I bet if the 13" comes out it will be 2560x1600. Which will be just as useable as the 15", just on a smaller surface.