Nah, I don't think it works that way. There will too many plot holes if it was. Anyway, Vice Admiral Bastille and his men still knew they have to capture some pirates in the island even though they have forgotten all their names on the wanted posters. Usopp still knows who Sogeking is and why he put on the mask on the first place. He just don't know who he had saved.
Anyway, if Usopp is setting up traps or doing some prep as he runs along then he could put up a little fight against Trebol just like he did against Luffy where he had a good fight strategy. Oda is just teasing us, Usopp WILL fight.