vint101

I'm trying to find a 3rd gen Tahoe to use as a tow vehicle for a car trailer. I want to find one with a heavy-duty trailering package (K5L).
K5L includes: GU6 - 3.42 axle ratio, KC4 - engine oil cooler, KNP - transmission oil cooler, NQH - 2-speed active transfer case

I was basically using the VIN decoder on this site to check the VIN's of all the Tahoes for sale in the area and couldn't find anything with these options.
I eventually found a Suburban that was advertised to have the package and asked a salesperson to send me a picture of the RPO sticker from the glovebox.

This is the pic. It clearly has all the K5L, GU6, KC4 and KNP codes. However, when I plug the VIN into the decoder (https://chevroletforum.com/forum/vindecoder.php and then look under Equipment) I get that this truck has a 3.08 axle, single speed transfer case and nothing about engine or transmission coolers.

So, is the VIN decoder basically useless for this case or am I misunderstanding something? How do I find a truck that I want? Is the only choice calling every individual seller and convincing them to send me the RPO sticker pic?
My understanding is that K5L package is rare and I'd rather not drive around to look at 40 trucks just to see they don't have it. As far as other identifying clues go - it looks like all Tahoes have the same hitch, not all 3.42 axle have K5L, some K5L have the built-in trailer brake controller and some don't. It's all over the place. And, of course, salespeople are clueless. I've been at it for a couple of weeks already and I'm at a loss.