2001 Blazer LS 4 door

Starting to have rust problems lower doors. I need someone to check their 2001 blazer and tell me if they only have 2 drain holes on the front and rear doors. I have checked a 1998 and the front 5 drain holea and the rear has 3. I have to find out if this a factory defect and GM dealerships are not being any help. They say the rust is caused by rock chips, I have had 2 other bodymen check it out and they say it is due to the lack of drain holes on the doors, perforated rust. I cant seem to find any GM website to contact on this matter