I notice the etched letters under the model number, they were put there by the maker and indicate what the holster was made for. They are not always present and frequently illegible but if you can make them out they'll tell you what the holster fits. Since you have a model 10 all's well that ends well. Thanks for posting it.
Regards,
turnerriver
Just got this in the mail today. Was hoping I might get lucky and it would fit a large frame but it's a for a medium frame 4". Shown with my Model 10.