I searched through my color chip books, and found no listing for DB 378. All the listings around that number are blue shades. I would stick my neck out a bit and say that DB 378 would not have been a yellow shade, some of the color families tended to be in the same run of numbers. For example, most (but not all, I grant you) of the reds run in the 500's.
The only listings for anything close to was DB 624 - yellow, DB 630 (early color) - yellow or DB673 - Sahara yellow, more of a mustard tone, DB 680 heliosgelb and one color chip of DB 1223 verkehrsgelb (this one is close) and is listed as a 1986 color in my Glasurit book.