TM 125 exhaust spigot??

[GMC]

What sort of spigot is normally in the barrel of the TM 125?
I'm looking at a TM 125 barrel that has a flange bolted on but it doesn't appear to actually bolt anything on!!
The spigot on the exhuast looks like it should fit over something but it's the outer of the pipe spigot that slips into the barrel.
Pipe spigot is around 45mm OD
Is this normal or is this maybe a TS barrel??

The stock TM pipe has an inner / outer sleeve in it.

I think I read here once that stock pipes have good bottom end & aftermarket pipes have good top end but sacrifice bottom end too much.

Any one care to comment on their experience.

Thanks in advance.

[cyclegod]

The exhaust gasket and seal arrangement is common to suzuki 100/125/185's right up to ER series and they all leak badly unless using strong springs and new seals changed regularly.