Experienced collectors and dealers can identity modern Proof coins by sight, with or without the packaging. Some 19th century coins, which are almost never with their packaging, can be trickier, but we are not dealing with those.
And thats another reason to be here on CT. There are both collectors and dealers that are willing to give their knowledge away for free. Ps First thing I did was look for the accented hair, and checked for the pointed 9 on the dime. The Accented hair in Mint packaging came with the pointed 9. It also has a much lower mintage than the Blunt 9. Which came after the hub changes. http://www.richardsrooseveltreview.net/1964.htm
Those would be proof sets (I think). Mint sets are mostly In softer plastic. You open them with scissors
