I can't figure out if the 723 is a serial number or model number...anyone know vintage bighorns??
If you email bighorn they should be able to tell you! I had great luck with them, I emailed with pictures of my older bighorn and the guy emailed me back with information about it and the page it was on in their catalog in 1969! It was awesome.
Also, that looks like a nice saddle! I love bighorns, especially older ones. Congrats!