For the AZ832 series relays from American Zettler, some part numbers seem to be missing symbols compared to others in the same family. It is important to note that the absence of a designator in the part number can actually be a designator itself. The below image shows the part number breakdown of this series.
For the Latching Type , Coil Option, and Contact Material Option, you can see there is nil as a designator. This does not indicate that there will be a space (or blank) in those areas, but rather it is an indicator for the lack of symbols in this area. This is a fairly common practice in the industry, although the exclusion of symbols typically applies to suffixes rather than in center of the part.