So after a little research (one phone call) I was able to determine what this mystery product is. I spoke to Bill @ Brothers Research, they are the ones that make the Duragloss products. Great company BTW always willing to answer questions and good products. He informed me that the Truck & SUV Polish (108) was discontinued quite a few years ago before they introduced DG105 Total Performance Polish. 105 is the replacement for 108. He also clarified where it fits into the other polishes as far as cleaning capabilities, I know this has been posted on this site a few times already but I figured it wouldn't hurt to update the list with this product. Here it goes, from the most cleaning capabilities to least/none:
501 RV / Marine Polish
108 Truck & SUV Polish
105 Total Performance Polish
101 Polish & Cleaner
111 Clear Coat Polish
Can't speak for any other properties such as durability, looks, easy of use etc. I haven't had the pleasure to use all of them yet. If there is an interest I'll give my two cents once I've tried the DG108 Truck & SUV Polish to see how it stacks up against the newer Duragloss product DG105.