The LH.com booking process used to show you a generic seat plan for the type of plane, but it looks like it doesn't even show you that when you are booking until later in the booking process. If your concern is what seats might be available, if you were to choose an ASR, then you may need to use an additional tool to see that. If you have an itinerary booked, and want to see the seats available, you used to be able to go into the ASR process and see the options, then just cancel out - I can't confirm if this has changed, but was definitely the case on my last LH group flights earlier this year.