No, I don't believe. Did he go in FSM with a simple dongle on 3.70? I think it isn't possible because from 3.60 you cannot more use jailbreak to go in FSM.
But to downgrade from 3.60+ using a flasher you need to be in fsm or you have to patch lv1. However I'll wait for more explainations from dospiedra, this news (and 3.55 modded) are very interesting!!
ps: uf6667 said "Also big surprise also for 3.56-3.70 users "