Should I update my iPhone 4 (4.1 to 5.0.1) or stay outdated? NEED HELP, PLEASE!!!!!!?

[xflair]

Ok, I know that this may be long but bear with me, really need your help guys!!!!

Ok, so a few years ago, I bought an iPhone 4 (I was in Zimbabwe, now in the US) that was factory unlocked from what I can tell. Reason why I "THINK" it's unlocked is because
1. It did not have Cydia installed when I got it, just stock with native apps only
2. Running on 02.10.04 Baseband (That cannot be Cydia Unlocked), I manage used several Network Providers and all Sim cards worked and still do, no problems. (Using T-Mobile Now)
3. Model Number is MC603B, and according to my research, it is a factory unlocked model.
Unless im mistaken???????

Here we go. The iOS 5.0.1 is out and I am now running iOS 4.1 (Jailbroken), which is really bakward, so loads of tweaks and apps cant run on my outdated iOS and i want iOS 5. I have heard people all over the internet complain that after the iOS5 upgrade, their phones locked-up and can't dowgrade or activate after the update, so if that happens im STUCK forever, and I really dont know what to do!!!!

HERE ARE MY QUESTIONS:
1. Is my phone really factory unlocked, based on what I listed above? Or is there any other way of checking???
2. If I DO update, do I risk locking-up my phone????
***3. Should I update it "while preserving my baseband" and still manage to Activate it, or just leave it to update my baseband????? PLEASE HELP. Read my questions carefully and answer on what you think.

Thanks alot guys

 

[TriJetHero]

1) if its not jailbroken and does not have cydia and ultrasn0w installed and is on BB 02.10.04 it should be unlocked. You can hook it up to TinyUmbrella and see if it give you the same BB

2) Updating an unlocked phone does NOT lock it

3) If its unlocked no need to preserve BB, if you are still unsure you can update it while preserving BB, you can than always unlock it with the Gevey SIM imposer

 

[xflair]

1) if its not jailbroken and does not have cydia and ultrasn0w installed and is on BB 02.10.04 it should be unlocked. You can hook it up to TinyUmbrella and see if it give you the same BB

2) Updating an unlocked phone does NOT lock it

3) If its unlocked no need to preserve BB, if you are still unsure you can update it while preserving BB, you can than always unlock it with the Gevey SIM imposer

THanks for responding, but here is the thing.
If I do update to iOS5 it will update my baseband! Now, because my baseband is 02.10.04 (which cannot be unlocked), I cant even unlock it even if I preserve my baseband. Making sense? So I should not risk it? Thanks again for responding