They are the exact same recording except 7" was mixed by Hibtone and the Eponymous version was mixed by Easter. They are in fact the same tracks but slightly different mix by different people.
Totally agree. Same RECORDING (from April 15, 1981 I assume), but different MIXES.
June 1981 - Bombay Recording Studios, Symrna, GA
notes: The band return to Bombay Recording Studios with Johnny Hibbert. They bring with them the two versions of 'Radio Free Europe', the one mixed by Johnny Hibbert, and the other mixed by Mitch Easter, and use the studio to decide which one to put on the Hib-Tone Records single. Hibbert's mix wins and can be found on the original Hib-Tone Records single. Easter's mix can be found on the 'Eponymous' compilation album.
R.E.M.’s debut 7″ single release of “Radio Free Europe”/”Sitting Still” later that year on Hib-Tone Records was based on these demo versions, but added overdubs and notoriously band-hated mixing work by label chief Johnny Hibbert. Easter’s mix of the post-overdub “Radio Free Europe” has since appeared on the R.E.M. compilations Eponymous (1988)