a simple bash one liner to manipulate files

I had to do create a single file from bunch of csv files, and also append serial numbers as first field in the resultant file after removing the duplicate entries.

Sample content of one of the csv file.
xx:yy:xx:tt:rr:pp
xx:yy:xx:tt:rr:xx
xx:yy:xx:tt:rr:xx
……………..

There were more than 20 such files with each having approx 50 MAC addresses. So I need to concatenate all those entries and put them something like this:
1,xx:yy:xx:tt:rr:pp
2,xx:yy:xx:tt:rr:xx
3,xx:yy:xx:tt:rr:uu
……………….

I know this is not a perfect way to do, but I can’t think of better. I’m more lazy than it seems.
It works though. Please suggest modifications.

seq `cat *.csv | uniq | wc -l` > 1.txt ; cat *.csv | uniq | paste -d " " 1.txt - > final.txt ;rm 1.txt