the answer is yes u need to claim the reward to confirm that u reached 100 activity to be able to do a free re-sign in of the missed day in the week.

for example u have not sign in this week on Monday 19th and Wednesday 21st of September 2022 u can sign in this missing days for free, when u have on Saturday 24th or Sunday 25th of September 2022 100 activity and claimed the redward.

but be careful if the last week of a month is ending before saturday is u can not sign the missing days of this week because a new month begins. For example the new month october 1st starts on a saturday, so u cannot sign in the missing days from monday till friday of for september in this week.

if a new month starts in a week for example 1st september 2022 was a Thursday and u havent been online on the days before but online have been online on saturday 3rd or sunday the 4th u will only be able to sign in the days of the week which starts in the month which will be Thursday and Friday.