are these the Low Profile Tracks? the part number I found online for the low profile seat track is D828TL, notice the "L" at the end. I am concerned about head height in my 1990 Fox and I am over 6' 2". I plan to buy the A4 seat as well. I know there is an "L" at the end of your part number but I am assuming it is for the doubLe locking feature.