Kawasaki Triples Club

Does anyone know at what point did they stop casting the 500cc mark on the H1 right cylinder ?

I had a set of none bridgeporoted H1 barrels off an A with the cc on both sides. My other 2 H1A didn't have them. I'll do some digging and see if I can find the frame number as I no longer have the bike

Thanks, my one is also non-bridgeport. I got mine separately from the 70 H1 I intended to fit it on.