I need help!! I'm getting ready to buy my first smoker. I've decided on the MES 30" but I am trying to figure out the difference between model 20070106 an 20071910. Near as I can tell one has a glass window and the other doesn't. I've been reading that if I go with an MES 30" that I need to get the 1st generation, not the 2nd. How Can I tell? Is that the difference between the two model numbers? Thanks in advance!