I was realized that a while ago but still I seeing some people thinking there are different editions of the games on the GOG.com .
For example those following games using that scheme:

http://www.gog.com/game/omerta_city_of_gangsters_gold_edition
http://www.gog.com/game/age_of_wonders_3_deluxe_edition
http://www.gog.com/game/sword_of_the_stars_the_pit_gold_edition

Everyone on GOG.com getting same installers . But there is a game card for that games and it's working like a game+dlcs bundle . And generally prices are better than getting those products are seperately . But after that all some people are thinking gold or complete or deluxe or whatever edition owners have different complete installers . It's not true . All dlc and base game installers are same . And they getting same product . But one user getting all of them in same time and others are getting it seperately . That's all :)

In all honesty, something that doesn't help so much, is that in some of the cases, even if you own all the DLCs, the Gold edition of the game isn't marked as owned. Contrast the two following examples:

1)Risen 2 Gold. If you buy the Gold edition, GOG marks both Risen 2 and Risen 2 Gold as being owned.
2)Sword of the Stars: The Pit. Even if you buy the Gold edition, GOG never marks SotS: The Pit Gold as being owned, but only the base version. A similar case occurs with Omerta; even if you have bought the Japanese Incentive DLC, GOG doesn't mark the Gold edition as owned. Needless to say, this can cause some confusion among buyers.

That's weird , because even Risen 2 have same base installers as regular edition . Only difference is setup_risen2_gold_upgrade_2.0.0.6.exe file . Now I am wondering is it a bug about other games ? or how Risen 2 correctly marking but others are not .

I know, I have the game. Thing is; I also have Sword of the Stars: The Pit and all the DLCs, yet GOG doesn't mark Sword of the Stars: The Pit Gold as being owned. Needless to say, this can cause some confusion (with a potential buyer thinking that the Gold edition offers a standalone installer).

Exactly even in Omerta forum someones are thinking Gold Edition have different installer . While ago they forget to the change patch version from Gold Edition page . And people were thought they have older installer than regular edition owners . That's really confusing .