Windows 7 Product Keys and Media Part Numbers

I recently read a post in a Windows 7 forum in which the poster
claimed that product keys of the OEM and retail variety are
universally accepted on MS media. That is, to say, if you possessed a
retail disk, that it would accept an OEM product key when doing a
full, clean install. Can anyone verify if this is true? If so, is
the reverse situation true, as in using an OEM disk to do an install
with a retail key?

Also, does anyone know where I can find a list of the MS media part
numbers for the various editions? The part number I'm referring to is
generally seen in the XNN-NNNNN format, where X is a letter and N is a
numeral.

Thanks, and enjoy the day.

6U