I found a used large BGE for sale. It is an older model and the fire box doesn't have the split in it for expansion like a new one does. And the diameter of the egg is 20" and I measured a new one today and it is 22". Should I be concerned with these differences? What should I be aware of before purchasing this used egg. The asking price is $700 with a crappy table. I intend to tell him $400 keep the table. Thank you for any help