If they were, the postmark date will hopefully be legible. Many more were sent enclosed in an envelope and the postmark shows only as a circular indent. More often than you would imagine held at the right angle, in the right light, dates can still be read from these.
The majority of photgraphers had their name and address printed on the back of the portrait postcards they produced. A minority had these same details embossed in the bottom right hand corner on the front of the card. This can be easily overlooked.
The stamp rectangle in the top right hand corner of a postcard often has the postage rates.
The word halfpenny was always pronounced heypenny. The word twopenny was always pronounced tuppenny.

Stamps of the following value and design were applied to Inland Postcards as shown.