i assume that any bmw official workshop will have a spare parts department in which you can order the original parts you would like (presumed they are available)
i don´t know if there is any fast service for spare parts in munich (i.e. in the museum or exhibition near the factory), I don´t think so, because I presume that the warehouses will be in other place, even out of germany sometimes
you can have walloth&nesch sending the parts to an address in munich (i think a hotel address will do fine), nevertheless w&n are far from munich so 2 or 3 days will be needed for the delivery to munich
i don´t have experience in munich but in berlin i bough the steering wheel for my e9, it was a fine second hand CLS petri wheel, so i think similar places can be found around munich but you will have to get local advise, or search in internet
regards