No use ordering one replacement....spares is where it's at.
I've used the flat springs on all my revolvers...been doing so for 35+ years.....when I have need of a new one, I order a half dozen. They are pretty universal...one type for C&B, one for cartridge. One of these types has fit all I encounter. Even at that, average life in my pistols is 8-10 years each.
Last time I ordered, they were $2 for C&B, $3 for SAA. BTW, you can often continue to use the "broken" spring with a little ingenuity.
To learn about fitting parts, timing a revolver, etc. the best buy is to look for a used brass-framed Colt. Buy some extra parts and have-at-it.
Regards,
Slim