Well im finally installing my new motor today/tomorrow/friday(taking my time )

I took out my opti to see that the small "o"-ring on the opti shaft are missing(i think that there is 2) .There is obviously a oil leak...

I just called my dealer and he doenst have any in stock

My question is simple:

-Can i go to any part stores like NAPA and just take 2 "o"-ring that fit on the opti shaft since its just a rubber ring?

Because they got a big box of different size of "o"-ring.

Thanks