Let me share my experience which is very similar. I sent my N810
(without battery) on June 2 by priority mail. They got it in a couple days, reported like
on June 6. They send me it back on June 12 and I got it on June 14.
The same part was replaced. It seems ok now.

What is interesting I did not lose any data during these 12 days. The only
thing I have to set when it came back was time and date. All other setting, applications etc were fine.

Finally (if everything will work) it does not seem so bad.