The 412's came with single triggers, double was an option. If you ordered it, either the dealer or the distributor installed them for you. I was the Valmet distributor for the state of Alaska, so i had 412 parts like that on hand at the time.
Scope mounts are available used, and also current Tika mounts, although not exactly the same as the old Valmet mounts will work on the old 412 bbl. sets.
I do not have any extra double trigger sets, or scope mounts forsale...
Drilling Man