I tried a hexdump command line utility and this is part of what it produced:
00000000- 49 44 33 03 00 00 00 03 5A 2E 54 4C 41 4E 00 00 [ID3.....Z.TLAN..]
00000001- 00 11 00 00 01 FF FE 45 00 6E 00 67 00 6C 00 69 [.......E.n.g.l.i]
00000002- 00 73 00 68 00 54 50 45 31 00 00 00 0B 00 00 00 [.s.h.TPE1.......]
00000003- 33 38 20 53 70 65 63 69 61 6C 54 41 4C 42 00 00 [38 SpecialTALB..]
00000004- 00 17 00 00 00 52 6F 63 6B 69 6E 27 20 49 6E 74 [.....Rockin' Int]
00000005- 6F 20 74 68 65 20 4E 69 67 68 74 54 50 45 32 00 [o the NightTPE2.]
00000006- 00 00 0B 00 00 00 33 38 20 53 70 65 63 69 61 6C [......38 Special]
00000007- 54 49 54 32 00 00 00 17 00 00 00 52 6F 63 6B 69 [TIT2.......Rocki]
00000008- 6E 27 20 49 6E 74 6F 20 54 68 65 20 4E 69 67 68 [n' Into The Nigh]
00000009- 74 54 4F 41 4C 00 00 00 17 00 00 00 52 6F 63 6B [tTOAL.......Rock]
0000000A- 69 6E 27 20 49 6E 74 6F 20 74 68 65 20 4E 69 67 [in' Into the Nig]
0000000B- 68 74 54 50 55 42 00 00 00 04 00 00 00 41 26 4D [htTPUB.......A&M]
0000000C- 54 52 43 4B 00 00 00 02 00 00 00 31 54 59 45 52 [TRCK.......1TYER]
0000000D- 00 00 00 05 00 00 00 31 39 37 39 54 44 52 43 00 [.......1979TDRC.]
0000000E- 00 00 05 00 00 00 31 39 37 39 50 4F 50 4D 00 00 [......1979POPM..]
0000000F- 00 0E 00 00 6E 6F 40 65 6D 61 69 6C 00 FC 00 00 [....no@
email....]
00000010- 00 00 54 43 4F 4E 00 00 00 3B 00 00 00 43 6C 61 [..TCON...;...Cla]
00000011- 73 73 69 63 20 52 6F 63 6B 3B 20 47 75 69 74 61 [ssic Rock; Guita]
00000012- 72 20 52 6F 63 6B 3B 20 52 6F 63 6B 3B 20 52 6F [r Rock; Rock; Ro]
00000013- 6F 74 73 20 52 6F 63 6B 3B 20 53 6F 75 74 68 65 [ots Rock; Southe]
00000014- 72 6E 20 52 6F 63 6B 43 4F 4D 4D 00 00 00 26 00 [rn RockCOMM...&.]
00000015- 00 00 58 58 58 53 6F 6E 67 73 2D 44 42 5F 50 72 [..XXXSongs-DB_Pr]
00000016- 65 66 65 72 65 6E 63 65 00 45 78 63 65 6C 6C 65 [eference.Excelle]
00000017- 6E 74 20 63 6F 70 79 43 4F 4D 4D 00 00 00 28 00 [nt copyCOMM...(.]
00000018- 00 00 58 58 58 4D 75 73 69 63 4D 61 74 63 68 5F [..XXXMusicMatch_]
00000019- 50 72 65 66 65 72 65 6E 63 65 00 45 78 63 65 6C [Preference.Excel]
0000001A- 6C 65 6E 74 20 63 6F 70 79 41 50 49 43 00 00 E9 [lent copyAPIC...]
0000001B- 1F 00 00 00 69 6D 61 67 65 2F 6A 70 65 67 00 03 [....image/jpeg..]
0000001C- 41 64 64 65 64 20 77 69 74 68 20 4D 4D 20 43 6F [Added with MM Co]
0000001D- 6D 70 61 6E 69 6F 6E 20 44 69 73 63 6F 67 73 20 [mpanion Discogs ]
0000001E- 54 61 67 67 65 72 00 FF D8 FF E0 00 10 4A 46 49 [Tagger.......JFI]
0000001F- 46 00 01 01 00 00 01 00 01 00 00 FF DB 00 43 00 [F.............C.]
This is a 5 star rated mp3 (a 100 on a 100 point scale). I do not see anything close to what I would expect for rating next to the 'POPM' reference. Where else might rating information be in the file? I can poost the whole hexdump file on Dropbox if it would help, but it's 47MB.