Usually the street K&N air filters should not use oil. Usually only foam air filters need oil.
What type of filter is it, paper type compound or foam?
You might want to re-read your K&N info. K&N filters come pre-oiled in many(most) cases. If you clean a K&N filter, (do use the K&N cleaner), you will need to re-oil it. K&N
cleaner is a citrus type and shouldn't be used on foam filters. Ditto that Uni
cleaner shouldn't be used on K&N filters.
I actually have both cleaners and oils in the garage at the moment for various reasons.
While they each claim the oil is formulated specially for each type of filter, (foam or gauze), there are no ingredients listed. I'd be most concerned about solvents in the oil or propellent doing damage to the foam, rather than any issue with the K&N gauze.
HERE is the MSDS for K&N Spray filter oil.
HERE is the MSDS for Uni spray filter oil.
If I'm reading them correctly, the Uni is a Aliphatic Hydrocarbon base (no benzine), and the K&N is an Aromatic Hydrocarbon base (contains benzine). This may suggest these are NOT interchangeable oils for the application at hand. The benzine may eat at the foam Uni filter, degrading it over time. How much time, I don't know.
FWIW, I have seen foam filters degraded by using the wrong oils, but couldn't identify what actual oils were used in those cases. It looks like the foam rots and it comes apart in granules.
You should be able to buy some foam filter oil at the local bike shop or auto parts store. Probably a good investment.
HTH