In a word YES.
Otherwise they know the option will be off the table, in rare case they find real dirt on another Judge. They will permanently lose the Filibuster.
It is nice to at least be able to threaten a Filibuster even if you can't deliver on your promise, the Press will eat it up. In this way they have a very small Victory.
The Democrat Party is doing this because of abortion. They
absolutely will not accept a pro-life, pro-family justice on the USSC under any circumstance. That is what this battle was really about. They swallowed three judges they hate in order to protect their ability to filibuster Rehnquist's replacement to death.
They could have been made to swallow all of the judges. We could have forced them to filibuster. But Senate moderate Republicans have no vision, because they don't care whether pro-life judges get on the court or not.