Osteoderms ID - Glyptotherium and Tortoise?

[HARanch]

I am new to the fossil Forum.  This is my first post.

 

I have 4 osteoderms I collected on the Brazos river Austin/Waller counties from San Felipe south to Interstate 10. 

 

I have numbered them 1-4.  I have identified Number 4 is a osteoderm - G. texanum most current name? I have seen G. Arizonia and G. floridanum, don't know difference.  No. 3, I believe is 2 peripherals from a much larger Glyptotherium osteoderm than 4.  Nos. 1 and 2 are much smoother than 3 an 4 and was wondering if they may be from a tortoise.