iPhone 3gs with Straight Talk

I bought an iPhone 3gs from ebay & had to factory restore to get the other persons stuff off the phone. The phone was jailbroke & to my understanding "unlocked" (it was orignally from AT&T)

I have been told the following:

I could not restore without doing the 6.0.1 update through iTunes.

I could not jail break if I upgraded to 6.0.1

I have to unlock my phone before I can activate it.

I found the following:

I could not restore to factory setting without updating- I called AT&T.

I can do a jail break once the phone is activated & ready to run.

I called at&t to get the phone unlocked ^ the first lady took the imei # but never came back on the line.

The second lady I talked to told me that unless the person who owned the phone called, that they will not unlock it.

So in the even that i can get the right person to unlock the phone- will activateing my straight talk SIM card and putting in the phone allow me to go on and activate the iPhone?