The box question has been answered.
The other questions.
Yes,, you can buy a set of OM parts & re-convert it back to an "as shipped" condition. And to do so,, is NOT hard if you have basic skills with a good screwdriver & a manual.
Spare parts to fit your gun will need to be for that vintage revolver. While not always seen,, they are also not uncommon to find. You can place a WTB ad in our "Classifieds" here & will likely get a reply. These parts usually sell for around $150.00.
The OM Ruger SA's are actually quite easy to dis-assemble & re-assemble.
An owners manual,, (free copies are available from Ruger,, or you can also go online to view them,) can walk you through it. A proper set of screwdriver bits to CORRECTLY fit the screw heads is the key to not marring the gun.