So I've had a model 1076 since 1999, I am wanting to track a little more history behind the gun, it does have the ability to fire with magazine removed and states that on the firearm.

Serial number is TFE1616

That serial number prefix is a prefix that was used for FBI issue 1076's, but is not exclusive to the FBI.

It appears the only way to know for sure is to pay the $100 for a letter of authenticity.  If it is an FBI issue gun, then that letter will bring more than a $100 premium (more like several hundred) if you decide to sell.

My 1076 is a TFE prefix reasonably close to yours and it shipped to the Virginia State Police in 1990.  Yours should have two dimples under the decock lever.