Keep that hunk of meat! Cryovac'ed stuff keeps an EXTREMELY LONG TIME!!! From everything I've read and cooked so far, I've learned that a solid piece of meat is good to go for a long time past the date usually, and ground meat is almost as long too as long as it kept real cold. I haven't been smoking too long, but I've been cooking meat for the past 7 years about 4 times a week.
The date's on there to make sure that the store doesn't get in any trouble for safety issues and they always stick to the extreme side of safe. Even if it did look like something might be up, if it didn't have an off smell I'd trim it to see if it's just the very outside. Then again I am beyond cheap and just can't stand to see a hunk of meat go to waste. Good luck on the cook!
Weber Spirit E-310, Weber Performer, Weber Smokey Joe, Mini-WSM, ECB Electric.