replacing exhaust

undefined rebuilding my 75 z1-900 and putting on replica 4 into 4 exhaust, I have taken a few off but never installed.
My question is , are there suppose to be any rubber grommets in mufflers where the mountig bolts go through to frame

Yes.

www.partzilla.com/product/kawasaki/92092...b0b593fee22d7168ca17

Nothing we’re the bolt goes through the mufflers. There is a rubber gasket on the OEM where the upper and lower connect. Not sure about the aftermarket. Type the part number in evilbay and you will find them.

www.partzilla.com/product/kawasaki/92059...b0b593fee22d7168ca17