Scam sites with different URL's are at large, also some sites that have info about ICO, says that official sites for ICO are not awailable/given out yet.??
Also till today what I saw about TON, I didn't got any clue for their original or truly their ICO site: TON/telegram,(one of many scam sites: https://ton.fund/) also didn't see any updates/announcments from devs, not that I was looking, but at this rate of getting info's about ICO's, announcments and other stuff should be eazy, I usually get more info if the thread/ICO that is on going, usualy there are some updates and info is everywhere and so on...
Since it's all weird and shady, I don't recommend you to just invest in TON, since finding real thing/info about TON if very difficult.
What I find other sites that you probably think are from telegram/TON, could be mostly a scam...
I cannot tell you if that site is official, since I don't know to what are you refering...
their official site: https://telegram.org/
I couldn't find their ICO site, and even this site: https://ico-telegram.com/ is weird for me, I mean, it could be all fiction/scam!!
I only got the info that pre-sale has got a lot of money(probably scam), and that in march the ICO ends, I wanted to work for TON, here with signature campaign, but their ICO is so awfully weird and I'am not trusting, I'll rather wait, and then maybe buy some TON... When I wanted to join signature campaign, on one page for telegram said, that TON/telegram ICO is upcoming, currently active and past...?? And I think at that time there was even a Bounty ICO, but now I cannot find it, or I was too much drunk that time? Dunno...
found this(not my opinion, just looking things from all angles): https://www.forbes.com/sites/jasonbloomberg/2018/02/17/telegram-ico-scam-among-cryptocurrency-scams/#992e1721cf00
https://open-gram.org/
wow? another one? and this site I got from ann thread.
Also something that has been said on ANN thread:
Telegram is nonprofit organization. How come they will arrange an ICO? It will break their principal.
My conclusion is that those are probably scams...