Any idea what this old 2 seater is?

[MichMan84]

I would get another close as possible build date copper Briggs. They might be danger-close to unobtanium, but a post in the wanted section might yield some information to help you. Rebuild the other and switch-out. Then re-build the other. No holes to drill, no buttons to push. And you have gained some valuable engine building experience.
Hope this helps, nice machine.
Steve

Thanks. I actually got the original copper Briggs running just the other day. I am now in the process of stripping the rest of the bike down, cleaning it up, paining some parts, and replacing a few worn out parts. I just need it done by July so I have plenty of time to make sure everything is perfect before I give it to my nephew.