As I stated in my recent post, I recently applied for a position and made a very stupid mistake in my cover letter. I used one of my template letters and, while I changed much of the text to customize it for the position, I forgot to change the name of the position in the subject line. Here's how it looks on my CL:

XYZ Company
Address
Attn: John Smith

Re: ABC Position

Dear Mr. Smith,

I am interested in the DEF position as advertised on... and so on and so forth.

The position at the top is incorrect. The position in the body of the letter is the one I'm actually applying to.

To make the long story short, I figured this was a lost opportunity. I mean, talk about crude and obvious mistakes... Imagine my surprise when I got a call from that company to schedule an interview, and for the correct position too.

Here's my question. What do I do about the mistake in the cover letter? Do I bring the corrected version of the cover letter when I go in for the interview? If so, how do I explain my reason for bringing it? Do I bring up the mistake and explain that I accidentally copied and pasted the wrong position in the upper portion (both of the positions are at the same company and were advertised on the same page, so that's actually believable)? Do I assume that they either didn't notice or didn't care and say nothing? Even if they didn't notice, what if they notice later and do care? Isn't it better to acknowledge the mistake and admit to a momentary brain freeze?

I urgently need some advice here. I would hate to miss out on this opportunity because of something so stupid. It's been my dream to work for this company since I was in college. Help?