Correct, I installed it before I shot the gun for the first time...
I did take it out this past weekend while out in the woods on a hunt, and popped off a couple of rounds at the end of it all to see what the difference would be...
I would say it's noticeable.. Not huge.. But enough you know its there (and helps)...
That said, my gun started off under 7lbs.. So adding another pound literally increased the overall weight by almost 15%... it's a short barrel .45-70 (18") with a youth stock, light optic, etc...
With you starting off with a substantially bigger and heavier rifle in that BC, it might not make as big a difference for you...