Your Leupold GR 12-40x60 is a decent scope. I had the non-HD in the early 2000s as well the HD version from 2007-2010 and the HD was good up to max power...40X versus the non-HD that seemed to top out at 30X. I like the HD version as it had great eye relief for an eye glass wearer and was relatively compact.
Ultimately I sold the Leupold GR HD to a buddy and bought a Swaro 20-60x65HD as I deal with age/horn restrictions on Stone and Bighorns (Dall too if I ever draw a tag), plus caribou (5-point up top plus back tine), moose (spike-fork,10-point), elk (6-point) and mule deer (4-point).
I'd rate the Swaro as 5% better on resolution based on using my GR 8 years ago versus a friends Swaro while on a sheep count and aging bighorns. Also the same results while comparing the two scopes while grizzly hunting so I bought a Swaro. That said, if my budget restricted me to the Leupold GR I'd happily use it and go hunt
However on a backpack hunt for sheep, taking your own scope is a luxury I would pass on. I'd take a peak through the guide's scope on occasion, and pack some really good binos and a glassing pad but I am older and don't want the extra weight of the scope and tripod (>5#s) if hunting with a buddy or guide who is packing them. You may have a different feeling, as you likely can't hunt sheep every year on a $60 tag like we can in BC. Good luck on your hunt!
