[berwynne]

As seen here:
http://www.latemodelrestoration.com/iwwida.pvx?;item?item_no=LRS-13550B%20%20%20%20%201&comp=LRS

The "LRS-13550B" that they have listed seems to be their own internal part number. The letters on the housing read "SAE-L-79 MG"

 

[tung]

You're right about the listed number being their own internal one. You want the '168' bulbs. That's the common trade number, and you can subsequently find these bulbs at any common parts store listed under this number.