NPM Trigger Trident w/ N

I know this Owner/Collector of M1 Carbines here that is retiring and ask me if I would be interested in any parts. Well of course I was. 2 of the several parts I bought were Triggers with a Trident and the letter N. I knew it was used by NPM by the books I have. What I didn't get from the books was are these early Triggers or Rebuild Triggers (late). I seen and heard both. There is the Trident then a dot then the N and another dot in the center not on the bottom of the letters like most are. My NPM has a SN marked Trigger. Would any other persons who have or had a NPM or anybody with knowledge of this would Please share some information about this. I bought several other parts that I've been looking for quite awhile with no luck and can't believe this guy had a few all this time. TIA.

Frank

Here are some pictures. I went to the store to get some Chalk, so you can see the details of the Mark.

According to WarBaby, Neptune Meter Company was a War Time supplier of triggers to NPM. - Bob

Thanks Bob, I did see that they were from Neptune Meter Co. I just don't know when they were used. I believe that these were sent very late in Production and made it on a few Last Block NPM'S . I was talking with some others and a data sheet showed from CCC Carbine that it had this Type of Trigger. If so, then it tells me that it was used on the very last of the NPM's.