The picture of the Lang you say is the same as yours does have an interceptor sear and, given the same maker and distribution of pins, it means you probably do have the same beast.
However, it is not unknown for the int. sear to be disabled by a previous owner or even removed and a simple spacer shaft put back in its place. There is also no guarantee that it is functioning correctly anyway.
Much the best solution is to remove the lock and find out what you have inside and then get someone KNOWLEDGEABLE to test it.
If you are not confident to do the removal yourself, find someone with experience and ability to do it for you.
