Thanks for separating the catalogs by manufacturer! Great help for research!!
Yankee and Deitz bars were identical in the mid 80s. The only difference I know of is Dietz offered two rotators with a forward facing "V" mirror (different fpm rates were offered as well). Jefferson County PD (Louisville, KY) used them on their cars and EMS vehicles.
1971 Yankee Catalog. Looks like emergency lighting was something they were just getting into. Didn't even have the 1166 teardrop lights yet. Most of this edition of their catalog was side-view mirrors.