The letters are just revisions of the same part normally. They may have changed manufacturers or made a small update. If there is a material difference, it will normally have a new number issued.I cannot find 68358392AB for a cheap price, I found it on one website which charges 400$ for shipping to my country which is ridiculous
Great thanks!68358392AB was replaced by 68358392AC. You should be able to find part # 68358392AC for less money as that is now the going forward part number. No difference in the bags. They change part numbers for a variety of reasons including different manufacturer making it for them or if a small enhancement is made to the part. I have this bag for my windows and it works great. Great protection for something that can scratch very easily if not careful. It is well worth the money.