Mine just snapped the clutch pull rod and because of serious oil leaks from the cylinder head area came back to this state :
As you can see your bike is mostly stock, just lacks some original parts, like fenders, lights and tank.
Be very careful changing oil, it needs oil added to the primary and oil filter cavity before you start it.
IMHO 73 / 74 are the best years for T150, 5 speed gearbox is a beauty and a disk on the front lets you ride faster.
Still they have lots of details which have to be absolutely correct to make them reliable, every day rider like my BSA
used to be.
We have a thread here about different improvements for those bikes, I think it would be helpful for a new owners
to have a thread about what to do to have them built properly, starting from the crank service.
This information is there in different places, perhaps it could be possible to have it here, everything in one place.