Always verify the legitimacy of individuals or organizations before sharing personal info or making payments. Do your research. RSA is not responsible for losses or damages caused by scams or fraudulent activity.
Here's a picture of this New Model Police .36 Cal with "AMERICAN EXPRESS Co. No 4" on the top strap.
I've been in touch with the Archivist at AE and they weren't aware they ever used Remingtons. He was aware they used the Colt 1877. Apparently they used the Remington before the Colt. Thanks for the look.