Tiberi and Del Toro were not at altitude before this, however for those who have been keeping their ears to the streets, Swart has been banging quite recently on about some new 'methods' they've been using, saying they are looking to eliminate the need for altitude camps, read into that what you will.
Jonas Vingegaard did not do altitude before the 2023 Vuelta, nor Pogacar before the 2024 Giro, for what it's worth. Heat training does mimic some of the effects, increasing EPO/Hb Mass/efficiency, but someone cleverer than me will need to say to what extent/whether it can be stacked with altitude.