I would also recommend taking photos of any and all attached parts you send along with the motor (alt, starter, clutch banjo, sprocket adapter, ignition cover, ignition plate, etc) and send them & a list of them with your motor.
When I sent mine for rebuild, I sent photos, a list, and copies in an e-mail for shipping and the engine shop still returned my motor missing parts. I sent it down with setup for black box with ignition cover and it came back with no cover, no ignition plate, and the button for the red box timing. I missed running the first race of the season with a fresh motor (luckily had a spare) because I spent a week fighting to get my ignition plate & cover back. I had to fall back on the pictures I sent along to get results.
I sent my motor down in early January and didn't recieve it back until middle of March. If they call you and ask if your running winter nationals in Florida, say yes. I said no and got pushed back a month. I had a buddy send his at beginning of February, and they asked him about florida, He said yes and got his motor back by end of February.
Do whatever you can to cover yourself. They will be dealing a lot more motors this year because of the re-sealing and there are plenty of bad experience stories out there.