Mark,
If it is engraved 1:8 it will be exactly that.
The slightly faster twists help stabilize heavier bullets in bigger calibres like the Creedmore. You don't need it in Grendel however because the smaller case favors lighter bullets. There are also potential downsides to faster twists so it's not just faster is better.
If you want to check, put an oversized patch on your cleaning rod. Start it down the barrel and it rotates with the rifling (as it should). Note the distance it takes to do one full rotation and measure.
If it is engraved 1:8 it will be exactly that.
The slightly faster twists help stabilize heavier bullets in bigger calibres like the Creedmore. You don't need it in Grendel however because the smaller case favors lighter bullets. There are also potential downsides to faster twists so it's not just faster is better.
If you want to check, put an oversized patch on your cleaning rod. Start it down the barrel and it rotates with the rifling (as it should). Note the distance it takes to do one full rotation and measure.