It is about 70% assembled when it arrives but there is still a good bit to do to get the printer working out of the box. It is the standard 2020 extrusion frame and every hole was spot on and the threads looked good where they were needed. The only issues I had were with the extrusions themselves and the Z endstop mount.
The 2020 extrusions are not perfectly flat on top, appears that with both the base frame parts, the center of the extrusion is just about a perfect 40mm, but the sides are 0.16-0.3mm shorter. I ended up shimming these but made a bit of an error which seems to have not mattered in the end. I had seen a video where somebody ran into the same issue and used some paper to shim, and others where people had to widen holes on the top cross frame due to the same problem. Widening the holes though seemed like an extreme way to handle it, and would not correct the geometry that is off (the verticals tilt inward - or possibly outward, due to the higher center on the 2020 base rails). I found that when I got it shimmed so the distance between the inside edges of the vertical frames was 25cm at the top and bottom (that is, they were parallel), the screw holes lined up on the top frame which indicates that it was manufactured correctly. The problem is that the vertical rails won't be parallel without shims, or a lot of luck. I also ended up shimming more on the inside edges of the frames since there was still a tilt to the inside after the initial round of shimming. Below is a pic of the problem:
Below are some pics of the shims and how I measured the 2020 base rails to get the sizes I needed (to start with):