Just can't tell from a picture that small... Maybe/Possibly...(Fingers crossed) but there is some crud around some of the letters - eg. the A of HALF, and perhaps the "P" is just a bit of crud??
I take it you don't have it in hand yet. Only a bigger picture or it in hand would be decisive.
My dad was a postie back then, and often worked on Christmas Day, usually up to midday. He and my mum were grateful for the overtime and exceptional payments, but for me it meant I had to wait to open my presents.😟