Lower Unit Seal Replacement ?

[Fisherball]

1st post, I think. Looks like a good site for someone with a 28 year old Johnson 70 hp that runs great. I've pulled my LU cuz of h2o getting in lube. Replaced shift rod O-ring, that's where a pressure test showed a leak. Also changing impeller & top drive shaft seal. I put the top shaft seal in & then learned from reading manual I should have put gasket sealer on the outside edge of seal. Anybody know if that'll be a problem? Some manuals go overboard. Think I should replace incorrectly installed seal, a $5.00 part. Always do it the stupid way!! Read the book after installing the part!! Thanks, Fisherball