The stores really were called Penneys (no idiot apostrophe present) until being gradually rebranded in the 70s and 80s.

some examples:

80s: https://commons.wikimedia.org/wiki/File:Downtown_Seattle_Pen...

70s: https://commons.wikimedia.org/wiki/File:FW_Woolworth,_Penney...

60s: https://commons.wikimedia.org/wiki/File:Penneys,_Eastland_Ma...

50s: https://commons.wikimedia.org/wiki/File:StateLibQld_1_46896_...

40s: https://commons.wikimedia.org/wiki/File:Seattle_-_Second_Ave...