While I realize you're probably just happy to get in there and get geared, that's a bit of a red flag. If literally EVERYONE else is in 560 gear then they should be at least starting heroics. They probably aren't very good or have lots of turnover.Normal SoO. It's a 10 man, and everyone is pretty much fully normal geared, ~560 ilvl.
To add in a note I don't think has been talked about - knowing the fights at an advanced level will convey expertise more then anything else. Certainly up until the highest echelons of raiding, trials rarely know the fights to anything more then a barely acceptable level. If you can buck that trend, you will undoubtedly make a solid impression to guild leadership, especially in a normal mode guild.
I joined a newly started guild progressing on hc, actually the first kill I had on my wlock (besides flex) was hc, I was being dead last, with some margin at first, though I brought quite a lot of experience and overall how to avoid taking as much damage as possible. And after a while a lot of dps too (topping dps in one of the last raids I had with them)
I doubt your experience will be just like that, but still as long as you show you are skilled people won't care if you can't bring the best possible dps at the beginning, you might even get some pieces that can bring you up to par during the first weeks.
Update, and some clarity:
The normal raid that I got trialed in was their alt raid. The guild is 11/14H, and this week they want to try me on their heroic group. And frankly, I'm scared shitless. The RL assured me I'd be fine as long as I read up on fights, didn't die to stupid things and did ilvl-appropriate DPS. Still, I'm not even full FLEX geared. I'm excited that this could be my step into progression come WoD, but I had only seen the bosses once on normal - with that alt raid. I don't wanna mess up on heroics.