Your starting assumption, that your “raw files are 4928 x 3264”, is incorrect.
The sensor contains a certain number of photosites, this number does not change. But these photosites are not pixels, and the data from them needs to be translated to arrive at what we called a pixel.
http://rawpedia.rawtherapee.com/Demosaicing
The image size discrepancy depends on how the demosaicing algorithm handles the information from the sensels (photosites) around the edges of the sensor. Some programs don’t handle them well and so crop them off which makes the image a little smaller; others, like RawTherapee, do handle them well and don’t need to waste them (or crop less of them off).
The metadata contained in your image reflects the size of something, but of what? Probably of the size of the embedded JPEG image. Every raw image contains one or more embedded JPEG images. But this number is not special or holy in any way. It just is what it is. And RawTherapee’s is higher, enjoy it.
http://rawpedia.rawtherapee.com/The_Image_Editor_Tab#Eek.21_My_Raw_Photo_Looks_Different_than_the_Camera_JPEG
http://rawpedia.rawtherapee.com/The_File_Browser_Tab
You can crop the image in RawTherapee if you wan’t it smaller, though why would you.