BK MD 2

Oxblood
I suppose this BMW lives somewhere in the Backnang area as Hockenheimring isn't far away from there!

Niemand
Oxblood
I suppose this BMW lives somewhere in the Backnang area as Hockenheimring isn't far away from there!

You are correct. The easiest way to distinguish them to have a closer look at the registration seal. This one has the coat of arms of Baden-Württemberg while plates from the Bördekreis have the coat of arms from Sachsen-Anhalt.

There are also special letter combinations used in each district, and that can be a bit confusing. If you are still interested, here is what I could find on the official sites.

Bördekreis:
One letter, one numeral -> Only combinations using B,F,G,I,O and Q.
One letter, two numerals -> Only combinations using B,F,G,I,O and Q.
One letter three numerals -> Only combinations using B,F,G,I,O and Q.
One letter, four numerals -> Not available since October 2013.
Two letters, one numeral -> Only combinations using B,F,G,I,O and Q.
Two letters, two numerals -> Only combinations using B,F,G,I,O and Q.
Two letters, three numerals -> All combinations possible.
Two letters, four numerals -> All combinations possible except (BK-NA1000 - BK-SZ9999).

Rems-Murr-Kreis (Backnang):
One letter, one numeral -> Only used on special request but without B,F,G,I,O and Q.
One letter, two numerals -> (BK-N 10 - BK-Z 99) without B,F,G,I,O and Q.
One letter three numerals -> (BK-A 100 - BK-Z 999) without B,F,G,I,O and Q.
One letter, four numerals -> All combinations possible.
Two letters, one numeral -> (BK-AA 1 - BK-PZ 9) without B,F,G,I,O and Q.
Two letters, two numerals -> (BK-AA 10 - BK-PZ 99) without B,F,G,I,O and Q.
Two letters, three numerals -> Not available.
Two letters, four numerals -> (BK-NA1000 - BK-SZ9999)

drumF
This is actually a very helpful info to distinguish between the two, as I recently spotted a BK plate that I couldn't well figure out if it was Börde or Backnang. Many thanks!