Just because its steel mounted does not mean it must look crude.
I would caseharden the lock, harden all the screws, the heads anyway, repolish then fire blue and fire blue all the other steel parts as well. Easier than browning and it looks better. Fairly durable too. If you want it darker fire blue then coat with oil and reheat to smoke off the oil. This will darken the blue somewhat and make it more durable.
Fireblue does not necessarily mean it is a bright blue, a little less polish will give a less brilliant blue especially if the temp is just past the bright blue color..
Dan