On the 1998 Cadillac Deville

Okay, On the Cadillace 1998 Deville 4 door all leather black seats and doors and sterring wheel and front of Dash looks leather also.The top of the dash has a matt finish It looks to me to be Vinyl. I like to be sure is it vinyl? I recently purchased the car from a private owner. And am just learning from people online, auto stores auto spa had out side of car detailed and just about a week ago got the leather seats and doors cleaned and conditioned. I know lexol  cleaner was used on leather  and then Lexol leather conditioner preservior. looks like they used same on the top of dash which now has not matted finish but more of a luster sheen like the interior. So what is the top of dash vinyl or leather, If top of dash vinyl continune like every 3 months or as need to clean /treat with lexol leather as with the leather, or should I use a seperate vinyl conditioner so stay nice smooth and prevent from dry out or cracks, ? this I wish to do with all leather in car all seats and doors  are very nice shape smooth and morist. Driver seat has some small crevices or cracks  but all else looks good previous owner did his own detail. I am new to all this and always liked the larger caddys . Since disabled have out sided done and washed etc, interior I think from now on can do myself  although its no very costly to have done if every 3 months or so, I don't drive much. so is nice since just drive local, my previous car was marquires 1994 got with 50k and got rid of it just over 9 yrs later with 81k.