Just to confuse things. And I'm relatively new to this whole ribbing thing....
As it's your spare prop, would you consider a brand new aluminium prop?
(I can hear the sharp intakes of breath already- a local powerboat racer describe aluminium props as something similar to spacesaver tyres, although only one of us in the conversation had been flung from a boat at over 50 mph and hospitalised, so it's about expectations really)
They don't cost that much.
Brand new condition = no question marks over condition
If you had any leanings toward a different prop size you can try it at minimal risk.
As it's a spare, you can use it as a selling point if you're ever tempted to change boat.
I have 19in aluminium prop on my 115 4 stroke which performs fine for my needs (spare is a slightly dinged High 5).