I had suspected some sort of airsoft or replica myself. My children have numerous toy guns, some of them quite realistic or with names suggestive of real firearms.
In BP firearms, .44 is far more common than .45.
I honestly do not know what age you have to be, or are supposed to be, to order antique firearms. They are not subject to the gun control act of 1968. An original Colt SAA or some such would have meant saving a lot of allowance money though.
State laws vary, but I believe minor children can have firearms here, they simply need a note from the parent saying it is okay.