No, we actually can't. In short, we've lost enough knowledge: https://space.stackexchange.com/a/6290

We can build a replacement, more capable than Saturn-V, and less expensive even. But we cannot reproduce Saturn-V the way it flew in 1970s.

It's like saying we can't build the pyramids anymore just because we can't build them the exact same way the Egyptians did. Is the goal to get to the moon or is the goal to build a faithful replica of the rocket along with a faithful replica of the tools that built the rocket?

We developed a particular pinnacle of tech and lost it through disuse. This happens in aerospace and high-end weapon-making areas regularly, because the runs are small, and much of the knowledge and technology is uniquely purpose-built, with thick layers of secrecy protecting the know-hows.

Speaking of military technology, humans lost the secret of "Greek fire" [1], which apparently was a medieval form of napalm, not extinguishable by water. All the current knowledge of chemistry did not help restore the recipe yet (because history studies have a smaller budget than the actual military, of course).

We haven't lost the ability to fly to the Moon, of course, because the principles remain the same, and the technologies advance. But we had to build completely different rockets, not reusing many, if any, bits of Saturn-V.

[1]: https://en.wikipedia.org/wiki/Greek_fire

It just goes to show that human progress is not monotonically increasing, we must travail to make it so, as without such effort, we slide back.