Disclaimer: I'm a Surgical NP and this is MY OPINION. I have worked in the OR for 13 years, first as a scrub tech, then CNOR, and now ACNP. Once again, this is MY OPINION. Some people get so bent out of shape :-) .
You don't need OR experience to become a Surgical NP. If it's a hospital where the nurses scrub and circulate, then you'll have a small advantage at learning the instruments, draping, sequencing, and providing exposure. Other than that, I think the only benefit to working in the OR is that you're able to network for future jobs. You can attend a RNFA program for 7 days and it'll teach you what you need to know to begin, then you'll go out and build on it while practicing. If you like kids, go into a pedi surgery practice, so you can get congenital surgery cases, reimbursement is pretty nice. If you don't like pedi (like me), spinal cases like fusions and laminectomies pay top dollar. Do not go into general surgery (like me), the hours suck! Good Luck!