Cooner's got it. Dickert worked through several eras. Because Dickert worked so long, the question is a little like asking, "would a Chevy have a carburetor or fuel injectors?" So you need to look at characteristics that point to a particular time frame.
If your Dickert has a buttplate of 2" or wider, and a sliding wooden patchbox or a simple 2 piece patchbox, it is an early style, and the barrel should be in the white or fire blued and of course the lock would have been color case hardened.
If your Dickert has a buttplate of 1 and 7/8" or so and a full daisy patchbox it is probably styled for 1790's and browning would be OK for the barrel. I'd leave the lock bright but browning it would be OK. In the white or fire blued is also fine- you have a wide open choice.
If your Dickert is full blown Golden Age with a narrower buttplate, any inlays, etc, browning would be most appropriate.