Replace...
If I am in a car with 4 wheels doing 75mph, I don’t care if a tire goes flat. But even a front tire blow out in a car could cause you to crash.
On a motorcycle that has the ability to do 180+ and I often take it over 160+, no way am I taking ANY chances with one of two tires blowing out on me.
Heck I replaced my rear tire when I was told I had another 1000 miles left on it.
I just don’t like taking chances. I guess the best way I can put it is this.
Take the tire down and ask the mechanic who is planning on putting a plug in it if he will sign a document stating the plug will hold at speeds in excess of 180mph
If the mechanic has enough confidence to sign a document that the tire will hold at highspeeds, then go for it.