Regarding the differences in the shaker and non shaker 340 FOUR BARREL nameplates, I might add that the 340 finish is brushed on the shaker and chrome on the steel, at least on NOS here. Also the 3 pins on the shaker are larger diameter and longer than steel hood one. Plus the pin on the BARREL end is in a different location on the shaker than on steel hood. A couple versions of the parts books have mistakes in nameplate part number listings.
Here's the backside of both and as you can see 3577361 is cast on the shaker and 3443246 on the 2 pin steel hood nameplate.
There was also a 3 prong 'CUDA 340 shaker nameplate along with a 2 prong steel hood version