There are a couple original (AD years period) that could work. The really rare 1947-48 vintage compartment lamp for sedan delivery bodies.
https://www.flickr.com/photos/advance-design_parts_co/13957537043/in/album-72157631868452754/
Took me years to actually find and win one, the kit contains a single Guide B-31 lamp and all the wiring and switch.
The next option would be 1953-54 BelAir switches. These are pretty common lights but it appears the switches were installed at the factory and you sourced the lamp kit?
https://www.flickr.com/photos/advance-design_parts_co/38938127131/in/album-72157631868452754/
https://www.flickr.com/photos/advance-design_parts_co/38938128251/in/album-72157631868452754/
https://www.flickr.com/photos/advance-design_parts_co/38051655075/in/album-72157631868452754/
If you are looking for period correct it may be worth looking at other GM division parts, switches and lamps were used across many models in the divisions.