They are essentially the same thing, the only difference is the layout of the form. There used to only be a LTC-100 form. Once the state made the classroom portion accessible online, they created another form called a LTC-101.
A LTC-100 only has room for 1 instructors credentials. Meaning only one instructor can fill out the form.
A LTC-101 has room for 2 instructors. The online class instructor and the shooting proficiency instructor. This is needed so that both instructors can properly fill out their credentials on the form to be submitted to the DPS. You will be issued an LTC-101 from our class with Part A filled in with your passing information and our instructor information. You must print and take this form to your shooting portion so they can fill out Part B and C showing you can safely handle and shoot a firearm.