Do these numbers match?
 

Does this add up?
A 912 with an engine number 4094067

Would that be the original engine?

There's no way of known if the exact engine number matches your chassis by just looking at it. The best you can come up with is whether its in the correct range or not.
In order to verify the exact number you will need a CoA from Porsche.

Certificate of Authenticity - Owner Services - Porsche Service - Dr. Ing. h.c. F. Porsche AG

That car has been around a bit. Not the original engine for a '67. Sharp looking car though.
Some history here: 1967 912 #354561