Go for it man. Don't worry about what the records are, they are no indication of what the other guys will be lifting. The record shows that some guy one time, and one time only, of all the meets, came in and lifted such an unusually high amount of weight, that it was a record. If the other guys were doing that same weight, than the record, well, it wouldn't be a record.
My very first meet was when I was 16, and weighed 198. I did a 440 pull and I came in 1st place in my class, even though the record was over 500.
As far as it being a big meet, that is the perfect reason to do it. I mean, you don't want to pride yourself in only competing in small meets that you will easily win, and then avoiding any meet that may present a challenge, do you? Would you rather say "I came in first place in so and so's meet" that nobody has ever heard of, and you only had one other competitor, or would you rather say "I came in second or third at this officially sanctioned state championship meet". Plus, don't sell yourself short. You may win. I was lifting the same as you, and I won.
As far as squats go. I would ofcourse try to find access to a squat rack, but really, fuck it.
If you can take X-amount of pounds, bury it, and stand back up, than it not like switching the bar from your arms to your back will suddenly take away from your leg power. I mean, it will feel different, yes, and who knows what you will hit, but its not like a 400lbs zercher squat will translate into a 200lbs back squat.
As far as you not doing bench, well, that was fine before, but this sounds like the perfect reason and time to get back to benching.
I would say put your game face on, grab you belt, and go kick some ass!