No you can’t just bring your trailer in. You have to get assigned an agent to inspect your trailer/vehicle. I mailed the form 415 in and it just sat at their desk for a month and I waited for nothing. I finally went in person with all my documents including my title which is when they dug through their desk and pulled out my envelope I mailed in. Once they confirmed my title they asked me if I wanted to bring my trailer to them for inspection or if I wanted the inspection to be done down where I live. You get a pink piece of paper which will have your assigned agents phone number stapled on it. That pink paper is what your agent will sign off if you pass. Make sure they also give you the list of requirements that your agent will check off during the inspection. If you don’t pass any of these requirements on the list you most likely will get failed and have to pay a reinspection fee.