On the 68 to 70 B-Body reproduction washer bottle, the cap opens in the correct direction as they were issued in the 68 to 70 time frame. In the mid 70's, Chrysler over the counter washer bottle had the cap moved to the opposite side. From what I was told, the move was made so that there would be less likely a chance for the lid to be blown open from air disturbance from the radiator or outside air entering into the engine compartment. These bottles were sold in that fashion up through the late 80's. During the mid 80's some bootleg washer bottles did get out of the manufacture with the lid opening in the correct fashion.
The reproduction bottles, no matter the application, do have a date code. Each one has a particular date that does not change, where as assembly line pieces varied on a daily basis.
As mentioned, the original washer bottle lids has a very slight lip that produces a circle pattern about the size of a quarter on the top. The over the counter washer bottles had on the lid, "Washer Fluid" spelled out. Also, on some of the A-Body washer bottles, the over the counter counter bottles are significantly heavier than the originals. So there are some subtle differences as compared to the assembly line to the over the counter to the reproduction piece on all of the different washer bottles.