It's going to depend on your insurer and the surgeon. I know they only did the initial check on benefit level etc. prior to setting my date. That said, my company is self-insured rather than fully insured, so they select their level of benefit and the hoops involved rather than having those set by an insurance carrier like BCBS, Aetna, Cigna, etc. With a different plan, it's likely to take longer. I've actually been beyond blessed on the insurance front as I won't end up paying a single dime (100% coverage In Network, no deductible In Network).
My timeline will be 2 months to the day from first appointment to surgery date. Because my insurance requires no weight loss trial, I got through appointments with a PA, Nut, BH, and my surgeon in one week. My first appointment was on a Friday and the following Thursday we were discussing dates. They actually offered me 9/19 which would be 42 days, but I have a family wedding to attend that weekend. I ended up with a 10/8 date instead.