Being that the hooked jaw ends were added before the bullet teeth, I would not expect to see the strait jaw ends on the bullet toothed jaw, they should be the hooked ends. Never say never though.

The hooked jaw ends were patented in 1902, however, I don't believe that they were used on Newhouse traps until 1908 to 1910. The hooked jaw ends were first used on Victor traps and not used on Newhouse until later. And, hooked jaw ends were only used on single spring Newhouse because jaw posts were bolted, no jaw ends on double spring until the riveted pan Newhouse.

That's what I've been wondering, here's a rough 4 pan 3 1/2 ?

Not all sizes changed fechers at the same time, just like different brands of traps didn't change at the same time. Your trap being a #3 1/2, compared to the #2 1/.

Gotcha, thanks for the fun education, very interesting

One thing I look for when trying to determine the age of a Newhouse trap and whether it’s correct is the nut on the bottom of the posts. The older traps usually have a thinner nut. The chains are a big tell too. You can date when a trap was made fairly accurately by the manufacture of the chain.

Isn't that also true with the spring eyes?

Depends which size of trap you’re talking about. The 21/2 was first brought out in 1882. All the springs are the same in length. The early traps all have flat springs that is no dimples on the spring eyes. The later traps had one side or both dimpled to get the loose jaw to lay flatter supposedly. From what I seen if you just crank the spring towards the dog side of the trap it usually does a good job of letting the loose jaw flop down all the way.