little dots above the iPhone's proximity sensor

Hello everyone, I have no idea if this question was answered, i searched the web and didn't find the exact answer so I really need someone to explain me the details.

I have an iPhone 4 White 16gb on at&t network(already unlocked) 4 months old. The digitizer glass above the proximity sensor's hole is clear without any dots, but I was browsing the web and found out that the iPhone 4 usualy has the little tiny dots above the proximity sensor, it makes even more confusing as I am trying to buy a new digitizer on ebay for another white iPhone 4 and have no idea which one to chose with dots or without them.

Please let me know the following:

- are the dots just on the iphone 4?

- are the dots just on the iphone 4 older version?

-are the dots just on the iphone 4 gsm or cdma versions?

- are the dots on the iphone 4s?

Second question is about the little lines that go through the middle metal bezel frame of the iphone 4 and 4s. There is a little difference between them and I would like to clarify that as well:

The Iphone 4 (as I think) has only 3 lines, one on each side at the bottom and one on the right side of the headphone jack.

The Iphone 4s (as I think) has 4 lines, one on each side at the bottom and one on each side at the top.

Yesterday one of my friends showed me his iphone with 4 lines and I told him that's a 4s, however he told me that it's a 4.

Please let me know the following:

- are the 4 lines only on the iphone 4s?
-are the 4 lines on the iphone 4s and iphone 4 newer version?

-are the 4 lines on the iphone 4 verizon/sprint/at&t?

To make it easier please see the following pictures:

http://img221.imageshack.us/img221/142/66832632.png

http://img151.imageshack.us/img151/3627/capturejxs.png

Thank you.