I believe the G grade was not introduced until introduction of the Two-Hook models. Apparently until this time frame the trigger adjusting screws were put on all grades. At some point they were dropped on all grades below the E.
As to their usefulness I guess it all depends on whether are not one has the ability to use them properly, personally I have no problem with them. You just don't want to set them so light as to be dangerous. Don't know how many times I see someone mention having paid Big money to have their trigger pulls adjusted, all I have to do is twist a screw driver on these with adjustments. Unfortunately they are not on the ones I use the most.
