I have a old Hawken and a old 54 cal Renegade about the same age. The Hawkens I still have the original barrel for it. It has a I believe the Green River barrel and the Old Redfield International sights on it. A friend who used to buld muzzleloads did the barrel swich for me. He did a great job on it. Made a bracket for the International sights. I forget how long the barrel is but it's allot longer then the original barrel. It uses a T/C Hooked breech. I haven't fired it in over 20 years. Just the sights today are very expensive.
My Renegade after many years of hard use the stock cracked. T/C sent me a new stock basically a new gun everything except for a new barrel and ram rod. I installed the new stock. Going to sight it in a month or two later I noticed the new stock was cracked again and had never been fired. This time I sent the complete rifle back. So my old Renegade has a new stock with the recoil pad. I'm much rather have it the way it was originally.
For a side lock it's hard to beat a old Hawkens and Renegade.