Is cystoscopy a standard procedure prior to TURP?

I was scheduled to have a cystoscopy but I showed the Dr a kidney stone I passed the day before and the Dr said I didn’t need cystoscopy because the stone was causing the flow restriction, and he scheduled TURP coming up in April. And based on my CTUrology imaging studies my prostate is not enlarged, so I am wondering if it’s really my prostate or is it scar tissue in my urethra from giving birth to a kidney stone 20 years ago, which is when my flow issues became obvious and more recently over the last 5 years I have dealt with prostititis which was finally resolved by taking a 20 day course of nitrofurinol.(sp) My question is:
Should the Dr have performed the cystoscopy before scheduling TURP? Is that standard operating procedure? Should I ask him to perform a cystoscopy to make sure it’s actually my prostate and how would I word it seeing as I’m not a medical professional and I don’t want to offend my Dr.