Ahead of the launch of Apple’s sixth-gen iPhone (which we’re hoping will be announced on September 12), the Cupertino, Calif. company has sent out an email to Genius Bars worldwide, warning of low iPhone 3GS stock.

According to 9to5Mac, “until further notice” Genius Bar employees are instructed to do the following when faced with a faulty iPhone 3GS, in an attempt to conserve the dwindling stock:

[offer] screen repairs, discuss the advantages of buying a new iPhone, and lastly, swapping out the full iPhone 3GS hardware.

Folks are even suggesting that, in the event of super-low iPhone 3GS supplies, customers looking for a replacement third-gen model could be offered the fourth-generation iPhone 4, instead.

Because the iPhone 3GS hit our shelves back in 2009, it has previously been speculated that Apple will discontinue this model once its sixth-gen iPhone (the iPhone 5?) launches later this year. However, that iOS 6 kind of supports the iPhone 3GS has led others to assume that the third-generation iPhone will remain on the market for a little longer, following the launch of the sixth-generation handset.

As 9to5Mac concludes:

Even with these apparently heavy 3GS supply constraints, it is still difficult to determine if the 3GS will be discontinued when the new iPhone launches.

If additional news hits the Web, we’ll let you know. Meanwhile, did you know the sixth-gen iPhone could launch with redesigned earphones?

Source: 9to5Mac