Not that it was planned. Originally, May 13th and May 20th were supposed to each air an hour of "Smallville" and "Supernatural". However, the CW decided to give "Smallville" a special two hour series finale, which obviously means that episode 21 of "Supernatural" will get bumped to the next week.
But instead of knocking the season finale to May 27th, they decided to show the last two episodes on the 20th.
When this was announced this morning, there were mixed reviews from fans. Personally, I'm excited. It's the first time there has ever been a two hour finale, and this has the potential for huge ratings. The CW has been pushing "Smallville" hard this season, and showing a pair of two hour finales on back-to-back Friday has the potential for a huge promotional campaign.
I don't know about the rest of the fandom, but I am very excited about this.