Transmission Numbers

I pulled out my transmission with my engine today and I saw some number on it and was curious what they mean.

It is a 727 and the numbers are 73 and then a bunch of boxes and then the number 3410432-2. Also on the bellhousing there is the numbers 432-2 with an X below the first two. The numbers on the bell housing are probably at least an inch tall and on both sides of the bellhousing. Also what color did transmissions come stock from the factory?

Thanks