Common in the 1950s-60s, these little (2.9″ x 4.2″) folios of ten color photos sometimes had a place for the address on the back cover and sometimes didn’t, which is the case here.  The cover says there are ten color pictures, and if you count the cover, then yes, there are ten.  What that means is:  we’re not sure if one is missing or not.  For that reason only, we call it:  Grade: 2