650 Exhaust screws

Couldnt find this in the archives but....
I have a 4-2 stock exhaust on my 79 kz 650 and somehow just noticed that the exhaust has a screw on each pipe coming out of the engine just as it starts to bend underneath the bike.... wondering if these had a pratical purpose or if anyone takes them out to get a little more sound?

Thanks

I don't think it came from the factory like that, and was likely something added in by the bikes PO for whoknowswhat reason.

Can you take a pic of it and post it here?
Maybe I might be mistaken on them being stock.

They did put the screw on some. It was either KZ650B2A, late 78 or B3 1979 used the screw. It was a standard 6mm bolt with a 10mm head. I guess used to drain water.