Yes, these are 350MHz probes.
Martin72, I read your frustration with the probes Siglent packaged with the SDS2000X Plus, I understand your sentiment especially compared to what Rigol has packaged with their scopes. For low end scope like this, the odd for someone paying for a bandwidth upgrade is pretty low, perhaps that's why they packaged it with the low end probes. It would be nice if they package the nicer probes with it.
Gandolf_Sr, the MSO5000 is a hobbyist scope compared to the Agilent you sold, so temper your expectation if you have not owned a Rigol scope before. It is an OK entry level scope with good value, but firmware update is infrequent (which partially drove Martin72 to switch to the Siglent) and its is sluggish at times. We also discovered hidden phone home behavior buried in the firmware, so I have to keep it on a physically isolated network as it can potentially serve as an attack vector for hackers. But for the low end models, it is a value buy, the fully loaded model is overpriced.
If your intention is to get a comparable replacement to your Agilent, I would stay with the excellent Keysight MSOX4000A series. The R&S RTA4000 with its 10-bit architecture is also intriguing, especially when you can get the all-in bundle promo at $12K right now. But you are also talking about scopes where you pay more in sales tax than what the Rigol costs.