Sorry for the delay in responding . . .
In theory, the answer to your question is "Yes."
In reality, you should monitor both the VHF frequency, AND the Viper talkgroup at the same time to verify they are indeed simulcasting, and it is tied together for all transmissions, not just the initial dispatch.
Nothing beats actual monitoring.
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Can't say I'm well versed in VIPER operations - haven't been here long enough and even then, it's a big state... however...
From what I've seen on both VIPER as well as other large systems, simulcasting of "local" activity - be it VHF, UHF, or even 700/800 activity - can be hit and miss. In many (newer) systems, the simulcasting might be automated such that if a radio switches to the P25 system talkgroup, the simulcast can/will appear but if that last radio leaves, the simulcast may then end.
In other cases, a "patch" to the P25 system can be dispatcher initiated - for either temporary tactical operations or even extended operations. However, eventually, the simulcast could stop without notice.
Then there is which site or sites a simulcast may appear on temporarily and it can apply to any of these situations.
And then there is my county - Brunswick - which seems to - in general - be fully on VIPER and simulcasting back to non-VIPER frequencies - sometimes.... Fireground operations in many cases here switch to non VIPER (and likely) non-repeater (or local repeater) frequencies.
Bottom line, as was already stated, there isn't a single answer to this question. However, a local regular user may be able to confirm their observations for your county.
These days things just aren't black and white, yes or no -- there's lots of grey.