You shouldn't have any issues returning that MES since you bought it from Sams.
Glad you had a great first cook on your pork butt. Yes the meat has a lot of fat so you can do "no foil", and the meat will still be tasty and not dry. Personally I like to foil for a bit, your right the bark gets mushy if you foil, so the final 60-90 minutes I uncover the butt to let the bark crisp up. One big reason for me to foil, is just like when you cook a turkey you get the drippings, which you can make gravy and sauces from. I like to take all the dripped liquid, put it in the fridge for 30+ minutes while I'm hardening the bark, and then separate the fat, using the liquid with no fat I add that to my BBQ sauce and adjust seasonings for flavor. You have to be careful, taste the liquid, sometimes it only tastes fatty even though you removed the grease. There are ways to get more flavor from that juice, but thats another post.
Also you can try injecting. 7 out of 10 times I inject.
Also after I pulled, I hit it with a little of the sauce I made, not very much just a hint so when you taste the meat you taste smoked pork, but you also have another flavor level from the sauce. People can always add more sauce if they want it.
On BBQ Pitmasters season 3 episode 8 or 9 they just had the Memphis cook-off, where they did Baby Back ribs, and Picnic Pork shoulder. Watch that show there are a LOT of tips for newbies.
