Did Perseverance and/or Ingenuity measure the local atmospheric pressure and local gravity where they are? Ingenuity had been tested in a 0.006 atm chamber on Earth, therefore I guess the local atmospheric pressure is about the same as the global average on Mars (and Ingenuity eventually did well on its maiden flight), but was such pressure measured by the probes on Mars, to make it safe? Did they also measure the local surface gravity, or their own weight on Mars perhaps?
Perseverance has been making pressure measurements daily it seems for a while: https://mars.nasa.gov/mars2020/weather/
750 Pa / 101325 Pa = ~0.007 atm
I believe most surface probes include an 'weather' station to monitor temperatures and pressures for science and engineering purposes.
As for the gravity part of your question, gravitational anomalies are really really small in most cases. Consider these kind of maps from the GRACE and GRACE-FO missions (Earth orbit):
Notice the units here are milligals, gals are an acceleration unit named after Galileo, 1cm/s^2 or 0.01m/s^2. Using g = 9.81m/s^2 means the local gravity field variations are about +/- 0.005%, not very significant.
On Mars these variations are larger, but still at most +0.27% difference from the nominal 3.721m/s^2: https://pgda.gsfc.nasa.gov/products/57
That being said, there was some more nuanced gravity field modelling for Perseverance's entry, descent, and landing. As I recall from one of the JPL webcasts (I don't remember which one, but it was pre landing with Al Chen talking about it) they noticed a slight drift (sideways motion) when Curiosity was touching down on Mars in 2012 and attributed that to a lower fidelity gravity model. They upgraded to a more accurate model for Perseverance using a "a local gravity correction to the to the onboard J2 gravity model", probably using the data from the second image above.
From Guidance, Navigation and Control for the Entry, Descent and Landing of the Mars 2020 Mission, Paul Brugarolas:
The EDL parameter update ground command provides a predicted bank command (pre-bank), ground derived navigation states to seed the navigation filter and a local gravity correction to the to the onboard J2 gravity model. The local gravity correction is new for Mars 2020. This parameter was added to mitigate the MSL touchdown velocity anomaly