I would strongly recommend that you take the time to do the fluid changes. Having the bike ready for a ride away will help with your ability to sell it at the best possible price. You have a little over a month before the riding season hits in your part of the world to get it done.
At a minimum I would get the engine oil, transmission and final drive, forks, and cooling flushed and changed. This is a job that can be done in an evening or Saturday afternoon.
If you have the time and feel real ambitious you could also bleed the brakes, but that would just be icing on the cake. Prep the bike as if you are going to take it on a trip. If indeed it was owned by a BMW mechanic, it shouldn't take much.
Rest assured that once the weather warms up a little and a few bikes get out on the road on a daily basis the shoppers will be coming out of the woodwork. Be ready for them.