Canada #1366/1366iis 52c Gravenstein Apple, Single Usage on Three US and One International Airmail Cover

Four covers, all mailed in 1995-1997, three of which were to the US and one mailed to the UK, each franked with a sheet or booklet single of the 52c Gravenstein Apple. Usage on the US covers was to pay the 52c US rate. The airmail rate to the UK in 1995 was 90c, so the only thing that makes sense is that the 38c difference was simply not caught by the postal authorities. The UK cover is franked with an AP printing on CPP, from a booklet and perf. 14.4 x 13.8. Two of the US covers are franked with perf. 13.1 booklet stamps from two different printings, both AP. A third cover is franked with a perf. 13.1 booklet single on Peterborough paper (CBN). The last cover is franked with a perf. 13.1 AP printing on CPP.
All very fine. Net est. $30.