I don't think there will be the demand to support the market premiums. That's not to say the Gladiator won't be popular, but with the Raptor and I believe the Hellcat (may be wrong on the Hellcat) the mfg only allocates a very small number of each to dealers. So they're not considered a limited run (i.e. Ford doesn't say we're only making 10,000 Raptors) but most dealers can only order 1-2 for the smaller dealers and 5-10 for the larger dealers. Often dealers, like LHM Ford in Sandy, will buy the allocations or the inventory from dealers out side this area so that they can have more on-hand. You can't walk in to a dealer and plunk down a chunk of cash and order a Raptor unless that dealer has allocations left (many will argue you can, I tried, I couldn't). They can't just get more allocations from Ford but they can get them from another dealer that may not use theirs (rare a dealer will let them go, especially out west). This is why it's super rare to find a Raptor that isn't the top of the line 802A package in a crew cab. They demand the highest price and the dealers can mark them up the most.
So, unless Jeep does something like that with the Gladiator, I don't think there will be a market premium. Also the "market" for the Hellcat and Raptor is pretty broad. I don't think the market will be as broad for the Gladiator. It's simply a Jeep truck, not a high performance, status vehicle.