Of Course. You can get within 4 months if lucky.

see this case:
This case got GC in 4 months

http://web.wenxuecity.com/BBSView.php?SubID=immigration&MsgID=207021

所有跟帖： 

• 回複：在這裏有許多人“證明”1-2天拿GC的，我就不信， -radiology- ♂ (168 bytes) () 08/16/2006 postreply 19:56:27

• 別說1-2天拿GC，一兩個月拿也不大可能，但是六個月是完全有可能的 -xiaobaitu- ♀ (283 bytes) () 08/16/2006 postreply 22:38:40

• It is absolutely possible -alohaahola- ♂ (164 bytes) () 08/17/2006 postreply 05:29:25

• 回複：10年前3個月也不希奇,現在,EB? -radiology- ♂ (0 bytes) () 08/17/2006 postreply 07:35:00

• 回複：記住不隻是I-485,樓主要包括I-140 -radiology- ♂ (0 bytes) () 08/17/2006 postreply 07:36:28