Those characters are J, X, E. When I look at the Sahara build sheets from others on crypto stickers I look for 20 × 8 inch wheels. All I have seen so far are 18 x 7.5 wheels.I've looked through the current detailed build sheets and have seen a couple of Recons but the Altitudes must of gone into the big completed list so can't find them.
I don't think the vin has a specific series number for the non-standard trim just one of the standard like Rubicon and then the different pieces called out - like the 20" wheels, decals. So hard to know if any had gone through recently. I read most of the build sheets when they publish but can't remember a High Altitude set. What are the characters in position 5, 6, 7 in your vin?