The BMW R12 has 4 possible frame number locations. Most BMW R12 motorcycles have frame numbers on section 1. If you look close you might find it here. If the motorcycle was delivered to the Military(Wehrmacht) than odds are very good its in section 1 or 2. If the frame number is not there look at section 3. If you don’t see it there than maybe in section 4. Section 4 is just for the P frame motorcycles. The P stands for pressed steel frame. It is the early motorcycles that have the P frames. It is not uncommon for the frames to not have numbers but don’t get discouraged, some frames were replacement frames and didn’t get stamped.
The correct frame font style should look like the photo below followed by two BMW Roundels on each end. This is always a big area of fakes and often wrong. The numbers should always have a German Gothic type ends on the numbers . You Can see clearly how it looks very German and old looking.
The BMW R12 also had a P frame number. This was nothing more than a large P followed by a number. The P frame bikes were the early versions and are sought after by BMW collectors. The Image below shows an original example of a P frame number.