Are you sure that's right? I looked at mine and they are both cast 5463633. In looking at them they are the same casting, just machined differently. I noticed that on both, the first 3 digits "546" are the same size. On one the number 3 in the 4 spot is a much larger font that any of the other number's, but on the other caliper it is the same size as the first 3. On both, the last 3 digits "633" are larger font than the first 3 or 4. The caliper machined for the passenger side which has the large 3 has a casting date of 20 while the other side has a date of 345. They go on a 02D car. This may be the craziest bit of detail I have ever posted about but to much is better than not enough.