They won't give you a frame to inspect, they'll have you inspect the frame you take to the test. It's hands-on.
No single grommet replacement. No racquetball gripping. No tubing.
At least try to understand what's in the study guide. For some things simple memorization would probably be fine.
For prestretching the gut probably you'd clamp one end of the gut into a starting clamp and the other end into another starting clamp, and you and the tester would each hold one of the starting clamps and pull, for at least 30 seconds.
It shouldn't matter if the knot you use is not in the USRSA guide, all they have are the double half hitch, figure 8 starting, and something else. The double half hitch isn't even a good knot, you won't see it used by tournament stringers, and instead of using a starting knot, use a starting clamp to start the crosses. As long as the knots are properly tied knots it won't matter for the exam.
You will have to apply a heat-shrink sleeve and replacement grip, and remove the grommets and install new grommets and bumper guard. So unless you have a grommet grinder or want to take a bit of time cutting flared grommets with snippers to be able to pull them out, don't take a racquet that comes with flared grommets.