Allegedly, and the fact that they have made it very clear everywhere, the Nano S model will be the only one that will not have that back door.
But how now are we to know? Doubts were left in the air, there is not much way to remedy it.
On the other hand it's unlikely that the backdoor has been there before because otherwise the hackers would have stolen the wallet seeds alongside the customer data way back when

You don't need to open source the firmware if you just open source the costumer data! *taps forehead*
What happened with Trezor? I remember a seed extraction hack from a couple years back, but that one still required physical access which makes it not even nearly as bad as what Ledger is doing.
That, and their partnership with Wasabi and blockchain analysis firms, resulting in government sanctioned surveillance and censorship.
Interesting, I wasn't aware of the censorship controversy around Wasabi. Thanks for bringing this to my attention.
(Still, in my book not even remotely as bad as what Ledger is doing for 2 reasons: (1) I primarily expect security from a hardware wallet, with privacy being a nice-to-have, but I don't mind falling back on other options for that, (2) using transactions with questionable privacy is still optional while having a backdoor is not. But I'll leave it at that, for fear of straying off-topic. I definitely see your point regarding SatoshiLabs' company policy though.)