New Thunderbolt 417 XLR

Not sure of the reason, but the 417 doesn't have the dovetail box. The structural explanation doesn't make sense because if that was it, they wouldn't send you one to install for fear of a structural integrity compromise. Perhaps it's just skipped because you have a 16' garage and you have so much storage space above? Not sure. I'll ask the next time I talk to someone there. As to installing it, maybe you could get the dealer to cut it in for you? If you're going to do it yourself ask XLR for the exact measurements of where to cut as you only get one shot at it. Either that or check another model at your dealer and measure it. Measure twice, cut once as the old saying goes.

Congrats on the new rig despite the box deal though! We love our XLR and I'm sure after you get any bugs worked out, it will make you very happy.