1970 Speedmaster Help

Omega newbie looking for help. I am being offered this Speedmaster. It currently has a cheap replacement bracelet, no box or paperwork. At some point during its life, someone scratched 10/75 on the outside of the caseback. I was told the watch was from 1970. Looking for any information on the watch and movement. How difficult will it be to find a correct bracelet as well as box and paperwork. Seller is asking $2200 US. Thank you in advance for any help!

No because I did not know. Very new to this.