I think the trigger from TOW is an early style, rather gracefully shaped and with a subtle reverse bend right at the tip. The triggers on the guns shown in the original post are thicker and clunkier, with more of a knob at the tip. TOW actually had these heavier triggers in stock for a while, but I saw them listed in the "Closeout" section of Track's website some time back and I don't think they are available anymore. The difference may be subtle , but it's there.
Considering the interest people have in Northwest guns, it is surprising how few choices there are for authentic-looking parts. There were several different trigger types, but I don't think these have been examined as carefully as locks and serpents.
Best regards,
Notchy Bob