Aerostar tire size confusion

I was just given this van. It's a '97 XLT. I believe therefore that it must be an all wheel drive. (When I look undernieth I see a rear-differential.) The previous owner has 215 70 R14's on there, but the door plate says 75 R14SLT (anybody know what SLT means?) is required.

How do I establish what the trim is on this vehicle? There appears to be many choices, as in: XLT, XLT Sport, XLT Plus, XLT Plus 4WD, XLT E4WD, etc

Any advice would be appreciated.

Get hold of a Chiltons or equal and they have a page which describes your vehicle using the VIN. It will tell you all the information pertaining to the drivetrain. XLT's are not necessarily AWD. My XLT is a RWD.
The tires are considered LT (light truck). Many tire manufacturers stopped making the 75 series for 14" wheels and so a lot of people have been going over to the 70 series. Be aware this is a shorter tire and will give you an eroneous speed reading. Cooper and Uniroyal still make the proper size tire for this vehicle and they are competively priced with all the other major brands. I used the Goodyear Integritys for years till they stopped making the 75 series and now I have gone over to the Uniroyals which I find to be very good tires.
By the way I have owned 3 Aerostars over the years and still have my 95 4L extended.