This note has been open for a while so I cross referenced these properties in the Clark County GIS portal and found the following:

- 5204B (as labeled on the current revision of OSM) should be 4811
- 5300B does not exist, that entire property is just 5302
- 5310B does not exist, that entire property is just 5308
- 5209B is just 5209

All the other properties in this area seem to be correctly labeled.