Price-wise, that sounds like a full-list price, but then it is tough to find local dealers who will special order Police guns, and ESPECIALLY a new, high-demand, non-standard model like this.
The only other option is to shop around locally, and try to find a FFL dealer who orders from a Remington Law Enforcement Wholesaler.
You might beat that price.
But, going by the "bird in the hand" adage, if you want it and can afford it, why not?
The trigger/sear spring is a direct exchange.
The purpose of the Police gun's heavier spring is to help prevent accidental firing under stress.
As long as you train properly and PAY ATTENTION, there should be no concerns with an exchange.
To switch the springs, you'll need to press out the large diameter hollow tube at the rear of the trigger group.
This will allow the trigger assembly to move back enough to allow you to pull the spring out, and insert the new one.