I don't want to rain on anyone's parade, but that web site might be out of date.
First of all, that picture is badly out of date. It is showing the original version of the SW 120ED. In 2018, they started shipping the "Evostar" models with the name placed on the side:
Then after the announcements here on CN and elsewhere about the glass, I received this model of the SW 100ED earlier in 2019:
Notice anything missing? Like the "Schott" label. I was surprised and sent it right back.
If anything, this scope tells me that Sky Watcher is no longer revealing their glass choices - and I don't think any of us can state for sure that they are using FPL-53 or even BK-7 in any of their Evostar models. I am sure we will continue to see out of date web pages for a long time - and I certainly hope SW doesn't let the quality slip on these wonderful scopes.
I have owned a couple of these scopes and they were wonderful scopes indeed. But I am confused and very upset that SW has decided to make us play guessing games about their scopes. If the manufacturer has something great to show off - they will shout it out to the world. If not, they will shut up and refuse to talk about it. Silence can be very loud.