...I wonder if they are actually taking me seriously as an applicant... I feel like its a hard call to make, and that I dont really know what to make of it. How is it with you guys?
Does it matter? They'll extend an invitation, and you have an opportunity to accept the interview or decline. If you decline, they'll probably wonder what the deuce you were doing there for the last month. If you accept, you will be expected to treat the interview as a legitimate one, and be on your best behavior. Either way, you won't realistically know what they think of you until Match.
This is not uncommon. I have heard of many programs that do this. After all you did have to go through some screening process to be approved to do an away there didn't you?
If they werent taking you seriously as an applicant why would they waste time having you rotate there?
I wouldn't read too much into being "accepted" for an away rotation. I don't think too many schools treat this as seriously as they do their true interview invitations. All I needed to rotate at an away was a pulse and confirmation from my Dean's office I was in good academic standing.
In the end, I received an official "Thanks, but no thanks" letter through ERAS before I arrived for the away, quickly followed that day by the program apologizing that there was a mistake, and that I did indeed have an interview, to be scheduled while I was there. That tells me they saw my app, outright declined me, then offered the courtesy. Despite multiple attendings being impressed by my performance, including at least one letter written on my behalf to the PD, good relationships with the residents, and supportive words from the chief, I didn't match. In the end, I'm sure my numbers represented a red flag the size of S. Dakota.
I'm not trying to tell you to give up hope. I have no idea where you are, or what your app looks like. I'm just trying to say there is no way you can interpret anything from a courtesy interview, so don't even try. Feel good that you have a month there to prove yourself, and that you have one more interview you may not have otherwise gotten. Give it your best, and you may end up there.