Find a good gunsmith to replace the part and go through the gun before you shoot it. Congratulations on a good purchase. Loading the .38 long Colt is not that difficult. It is not the same as 38 special.
The bolt spring is definitely broken so I’ll start there. Everything else seems to be in working order. The nicks and dents are only cosmetic with the overall finish being vg+ considering it’s 120+ year age. Cylinder locks up tight when the hammer is released so it should be a good shooter. I’ve done work on several Walther P38s, Oberndorf Mausers as well as original Mannlicher Schoenauer set triggers among others so I’m not intimidated by a challenge.Guess I am a yokel because I have worked on a few old revolvers for a friend with good results. That said, your gun's cylinder has some marks that give me pause.
There are still a few good gunsmiths that will work on old revolvers, just difficult to find and usually expensive. Might check with some local gun clubs or ranges. They can sometimes point you in the right direction when a specialist is needed.
Springs are usually the easiest of parts to fit into an old gun for a DIYer.
Might try a complete disassembly and cleaning before buying parts. Dirt and debris can build up and create issues similar to what you describe. If a part is binding because of debris, it could be more than the spring is meant to overcome. Even seen a couple of "safe queens" that were full of dust and debris. Many times on old, used guns, a good cleaning is all that is required to restore full function and safety.
Again, yours appears to have marks indicating more is going on than the problem you describe. Perhaps it was used to hammer nails into fence posts by a real life cowboy.
Good luck, sir.