The Wayne 90 series pumps that had a "F" was the ones that were lit by a fluorescent light, rather than by regular bulbs. 90 parts and repair manuals list a F-1, but no F-5, but thay don't explain what the 1 is even for.
I have color ads, color sales literature and parts/repair manuals available for this pump, if you are interested, please email me: jhsim@swbell.net
Jack Sim

Author, 1st & 2nd editions of Gas Pump ID book, 3rd edition is now available at www.gaspumpbible.com
Air Meter ID book also available