I'm not sure there's anything official, but local Enterprise reps do see your status. One of the local branches I used fairly frequently before the pandemic would tend to give me the nicer cars/lower mileage cars on the lot despite my midsize reservation. That seemed to be very YMMV based on location though, as other locations I was lucky to get a base Corolla.

One thing you might want to try is to see if your corporate rates are cross-brand. My corporate contract ID from National gives the same rates at Enterprise.