Next steps, send the VIN to
[email protected]. State that it is from your family estate and you would like the production information. You will hear aback within 24 hours.
I also recommend that you have an E9 pro evaluate the body. That will help you land on an informed value. There are a number of professional and amateur e9 experts in the bay area. You just have to find the rust. You don't need a quote on the cost to fix (extremely subjective). Fortunately the problem areas are well documented and for the most part, the rust is easy to spot. There is a lot going on inside the rockers, and you can't see all of it. Like a tooth, if the outside is visibly rotting, you can assume that the inside is shot. So you are looking for exterior rot, preferably underneath the cosmetic fender covers (which remove easily in theory but the screws are likely stuck/stripped). If you have an impact driver (aka super powerful screwdriver), that will either force them out or snap the heads. Either way works for a car in this state.
You can also run a $30 scope from amazon through the rocker.
Without listing the car outright, I can think of four potentially interested parties that like to hoard and/or flip e9's. These guys are easy to sell to, but don't expect to see a restored car in two years. This car is great for someone with the time and money to get into the game, because it is assembled. It is really hard for folks to restore cars that come in 32 boxes unless they have one to reference, or they are an e9 restoration pro. I think that the car may do well on Bat also, but the rust comments will be driven by sentiment and hearsay not facts about your car.