Copying a specific TM backup...

Odd question/scenario:

I am recovering from a HD crash and I decided to just manually copy over a TM backup from an external HD so that I could manually sort the files I want to keep. I copied a folder, one of the dated ones (e.g. 2012-05-10...).

At first, it asked me for my admin password which I thought was odd but I thought it was because there was movement of old system files. Then I noticed things popping up in my Trash. Then an error box popped up asking me if I wanted to replace a file or not... Now that was weird. I ended up stopping the whole copy process as I was afraid somehow these files were overwriting my current OS files.

I thought that the folder would just copy over like any other folder but it seems as if I am wrong. What happened when I copied over the backup folder?

Thanks

P.S. I am running Mountain Lion. The backup I was copying over was from Snow Leopard.

EDIT:

The things popping up in my Trash was because the external HD had some items in its trash can. :slap head:

However, I guess my question is: nothing on my Mac should have been modified due to me copying over an old TM backup, right? (I dragged the backup folder to my desktop and eventually cancelled it)