I'm glad you posted this set. At first glance this looks 100 per cent original but I have some concerns. I have a similar set I recently purchased off of everyones favorite web auction house. The control number was pretty much obliterated but it was not one of Bens repo boxes. The fragments that remain might be the same as yours. It was sold as a repo set but I purchased it as it looked original and I wanted to examine them. After I received the syrettes I contacted the seller to enquire what the story was as they looked so authentic. He stated he won them at a storage container auction and believed them to be real but had auctioned them off on a Buy it Now as repros so they would not get pulled. He would not give me any more info. The auction was pulled after my purchase. My box had the rub marks like yours inside from the syrettes and was moderately worn on the outside. The syrette plungers have a round end rather then triangular and I don't believe I have seen that before. Mine are round also. My box does not have the Tax stamp. When you handle this in person they look original but I just don't know. Maybe we can get some more input on this.
For me, this item is an original piece. As Kevin has already indicated, it is possible to find Syrettes with both shapes of plunger ends (please see the photograph below which was made from two originals in my collection):