You’ll want to head over to Vintage-Sierra.com to check out the article about looking at Sierra boxes / packaging / stuff. This is a huge area of discussion. I plan to sooner or later setup an article with more information than what is at that site (such as going down to the specifics of each varying release), but it’s a great starting place.
In short, Sierra did have cheaper redistributions of their games, often either “slash” releases or “value-priced” releases. Anything with black-and-white photocopy-quality manuals is considered a “slash” release (budget release) and not a true Sierra release. These boxes are not identified. The box colors of these had great variation, white, black, grey, even the same game released as slash could have had different box color variations. The other kind, “value-priced,” often had various yellow circular stickers on the box – and these often had boxes and manuals that were just fine in terms of quality but perhaps not the same as the original release (but I can’t recall if these were actually Sierra-distributed or not). There are many other cheaper releases of Sierra games, some by Sierra itself, that probably not all variations of have been discovered yet.
I’m not sure what slash CDs were like, if there ever were any (there are “Value-Priced” CDs), but the slash disks were cheaply produced and usually had plain white labels and no Sierra logo or the usual type of wrap-around label that you see on Sierra disks.
The Space Quest IV box with emboss is an original. Without emboss, I don’t know for sure in this instance, probably a slash version, especially if it is one with a photocopied manual. Also at Vintage-Sierra.com you can check for pictures of what the contents of each box should have in the original Sierra release.
The slash releases are pretty much worthless by the way – unless of course you just want to play the game. But you have to be careful on eBay.
Hope that helps!
Perhaps I’ll start working on that article sometime soon, showing examples from my own collection. I know it would be a great resource to be able to look at what specific boxes and items should be like in detail.