The Time-Life numbering scheme is 2CLR-xx. Sound levels are a bit low, but the insanely thorough track selection makes up for it. The Time-Life numbering scheme is R988-xx. 14, 17, 18, 20, 22 and 23 are mastered by Dennis Drake. Some of the levels are inconsistent, track-to-track. On the whole, they're excellent, but there are some oddities, like the last note being cut off from The Power Station's "Some Like It Hot", and inclusion of the too-long album version of "Freeway Of Love".
Both pressings have identical serial numbers and the only significant difference in artwork is that the "1977" watermark on the rear cover (not shown in my b/w scans, unfortunately) is tilted for the original release, and horizontal for the rerelease. Later pressings replaced it with Earth Wind and Fire's "Serpentine Fire". The original pressings of this CD had Abba's "Dancing Queen" as track 2.
(You can use this as a checklist - it's complete.) The scans are all 300 dpi black and white pdf files, suitable for printing. There are 48 CDs in this series, and they're all shown below.
Very few tracks are mastered from vinyl, and you even get Bee Gees cuts! Needless to say, you should buy any of these if they turn up used most are out of print (dang!). The "Sounds Of The Seventies" collections are the largest and best-sounding '70s collections I've ever run across, anywhere, ever.