Does Costco have a good selection of top shelf whiskey?

Nope. They'll have a few things, usually a couple that look like barrel picks but aren't a great price for what you get. Not a bad price if you want a mid-grade known name. At the one here they carry a few decent local ones, but not enough variety for me to try find new and not nearly enough high proof stuff to get my interest. If you are making old fashioned's, you'll be fine.

Definitely nothing worth driving 45 min for. Best thing at the Lafayette location lately has been makers or 4R SB.

Baton Rouge location. Elijah Craig $24, every where else in town $32. Sometimes they’ll have Angels Envy and usually Four Roses. All good bourbons.

they'll occasionally have a drop of allocated bourbons (blanton's, etc) but it's few and far between

costco is my go-to for rare breed ($40) which is what i keep in stock at home

Costco isn't really known for having a large selection. They, of course, concentrate on volume. I've bought Angel's Envy, Woodford, Basil Hayden, etc in there, but normally end up walking out with just a 1/2 gallon of Elijah Craig ($49) and a couple of bottles of the best deal in the store, their Kirkland vodka ($14/half-gallon).

It'd probably be worth the drive if you're going to stock up and you don't have better options nearby.