I suspect the numbers and colours are the same in all the different products.
First dose is always No6 Blue Top; according to my vet, there's no point in a second No6 Blue Top in a pre-lamber.
In a pre-lambing scenario, you would switch to the No2 Green Top after the initial No6 Blue Top; post-lambing you just use No6 Blue Top.
If you don't have a Green Top, and your pre-lamber doesn't rally after the initial No6 Blue Top, perhaps it's best to ask your own vet for advice on further treatment.