It could be an early TR but mine and others I looked up on the Internet just now have very different formulations of the "T" in the first name and "R" and "t" in the last name.
I did find one from 1889 and it was slightlly more like yours.
I also looked up TR Jr's signature and it doesn't really look like his, either.
You asked for opinions and I gave you mine. You can disregard as you see fit.