No. The touchscreen firmware's source is not distributed[1] for one, and neither is the firmware for the baseband processor. Possibly more aspects.

Although "open" doesn't matter as much as "libre" does. Modifying source code is useless if you can't actually replace the running instance. It has all the same problems as closed source software. Baseband processors are legally required to be tivoized, thus the violation of user freedoms is encoded in law. Quite frankly, I think it's a huge mistake on the part of regulators. If somebody wanted to do undesirable things on cellphone bands, they can simply build their own transciever for it and there's effectively no way to stop that. These regulations aren't a real security measure, not even security through obscurity. Making a transmitter for a certain band is trivial if all you're doing is causing interference. If the malicious actor is doing more than just that, it already requires a strong understanding of RF principles such that they already effectively posses the knowledge to make an appropriate transciever. All regulators effectively do here with Tivoization is protect potential back doors and security vulnerabilities from being mitigated.

[1] - https://docs.puri.sm/Hardware/Librem_5/advanced/firmware.htm...

Which proprietary blobs in Sailfish OS are worse than the others you were referring to?