Rinehart slimline duals.

[HDSlicer1]

Can I run these headers and dbx4.5s with stock ac/tune till I get the tuner?

[rigidthumper]

Can you? Sure.
Have others? Yes.
Should you? Maybe, maybe not.
The factory map is a "one size fits all", and is designed to meet CARB/EPA/DOT parameters, while maintaining an acceptable level of driveability/performance.  Most folks think it's fine, and add slip on mufflers and ride until trade in.
Every bike benefits from a proper tune, and calibrating the ECM for the components installed ( including the stock components) results in a smooth, happy, and efficient motor. The farther from stock you make it, the more benefit you will receive from a proper tune.
(It's an air pump- if you add more air in/out, you should add more fuel)

[Hossamania]

At the minimum it should get a flash tune with a preset map set up for that particular combination. It won't be perfect (or it might be), but it will be much closer to what's needed than just leaving it untuned in any way. Which means you would have to buy a tuner.