Display Assembly vs Display Assembly Kit (post water damage)

Hello everyone, I'm kind of new on here and would appreciate if anyone would help me out on this... I have a water damaged Iphone 3GS, damage consisted of a non-working home button and no backlight in my screen. Now I've read the guides on cleaning out the phone, and I was actually successful in restoring my home button function, however I was unable to restore backlight funcion. My wife has a 3GS as well, so out of curiousity, I borrowed her LCD Dissplay Assebly Kit (yes the whole front where you just disconnect ribbons 1,2,3) and sure enough, the backlight was functioning. My question comes here...now that I know there is no problem in my motherboard and the backlight will work, can I just purchage a Display Assembly and replace just the LCD, or is there a possibility damage could be done elsewhere in the Assembly Kit and would then have to pay 100.00 for the whole assembly kit as opposed to a 70.00 or even cheaper LCD. Remember..*I used my wife's Front Panel of her Iphone and the backlight did work so there is no mother board issue. Any input would be great!