Let`s make sure you are clear on what this listing offers, exactly.
Basically
This listing offers a door interior weatherstrip.
Driver or Passenger Side
The part being offered here is for the driver side in the context of the US market.
Front or Rear
The part being offered here is for the front of the vehicle.
Color
The color is Black.
Fitment
The part being offered here is expected to fit
a BMW 5 Series, 3rd generation. Another name for this model series or body style is E34.
For the US market, the part being offered here fits the entire model series range.
This part fits all of the years for this model series: 1989, 1990, 1991, 1992, 1993, 1994, and 1995.
This part fits all of the body styles for this model series: 4-Door, and Touring.
This part fits all of the model names for this model series: 525i, 530i, 535i, 540i, and M5.
Part Number
The part number officially assigned for this part is 51218102823. The parts literature sometimes shows the first four digits of the part number separate from the last seven digits, like this: 5121 8102823. Sometimes they use periods and dashes in the part number; sometimes not.
Pictures
The pictures you see on this listing might be of the actual part(s) you would be buying, or it might not be, due to how multi-item listings work.
Tech Notes
Variations
For the E34 front door interior weatherstrip and chrome-style trim strip moulding, the general design is that these two strips are clamped together using six steel clamps. The part number for these clamps is 51211928189. We have seen them in a brass color and a black color. On the E34 the black ones tend to be used, but you might see brass-colored ones too.
If you need to replace just the weatherstrip or just the trim strip moulding but not both, then you can reduce your expenses if you separate the pieces and purchase only the replacement component that you need, then re-assemble the good pieces.
The chrome-style trim strip moulding profile looks like the letter "T" ... the driver part number is 51211944715 and the passenger part number is 51211944716.
The black weatherstrip profile looks like the letter "K" for one variation, and the letter "Y" for another variation.
We are not sure why there are two variations, and when the change was made from "K" to "Y", or the part number implications. We have recently worked with one of the latest US-specification E34 cars to be built (October 1995), and we noticed that the "Y" shaped profile was used. These parts do not have part numbers legibly stamped on them but from what we could figure out for this vehicle, the driver part number is 51218102823 and the passenger part number is 51218102824.
We are not sure for which model years the "K" shaped profile was used. This variation also does not have part numbers legibly stamped on them but our best guess is that for this variation, the driver part number is 51211944719 and the passenger part number is 51211944720.
Are these two variations interchangeable? We do not know.
Quality
The part we are offering here is a used but genuine BMW part. It was most likely original equipment (OE) installed at the factory when the car was manufactured. The company who supplied this part is the Original Equipment Manufacturer (OEM).