Its been 13 years since I hunted the Bighorns and even more relative to the Snowies and Sierra Madres. I'm in the far West now. I expect others are giving you more up to date info than I can on the former ranges.
There are a few resident grizzlies south of Jackson. One frequents the area directly east of southern Star Valley (Afton area) and I expect there are a few more other than passing through up on the Grays. A kid was charged by one a few years ago. It was fortunately a bluff. I saw a young grizzly up Strawberry Canyon about 7 years ago and tracks have been confirmed along the Idaho Border. A reliable report came from a hunter who crossed paths with a sow and cub up the Little Grays last fall. The sow was not aware of him and he chose to hunt a different area for the rest of the season.
I wouldn't worry about it. Bowhunters seem to be having more close encounters with lions than bears. Carry an easily accessible spray and enjoy the hunt.