I plucked up the courage and installed it iOS 4.3.5 on my terminal to find that the baseband in the new version of iOS remained unchanged on iPhone 4, that is, it is still 04.10.01. Considering that we are talking about the same baseband, theoretically you should still be able to decode using Gevey cards because the vulnerability used by these cards should still be available in the baseband. In order to block the Gevey cards, a baseband update was needed, but since Apple did not implement it, the decoding gate theoretically remains open.
Regarding the possibility of jailbreaking using redsn0w, I inform you that I managed to jailbreak without problems, but with version 0.9.8 beta 4 of the program. This time Apple has not blocked the method used by the Dev Team to jailbreak our terminals, but unfortunately we are still talking about a tethered jailbreak so it won't help you much. I for one do not recommend you to update to iOS 4.3.5 unless you need jailbreak or unlock (for now) because this version of iOS does not bring anything new at all.
