No offense to Bill who believes that all 150s are the same, but a super-clean 1978 with nice paint, nice interior, VFR GPS, and only 850 hours on it is probably worth $4000 more than a decent 1968 with 3000 hours on it.
Absolutely no offense taken at all!
Sounds like it is all working out for you! A very hearty congratulations! Now, since you are so close, when are we going to get together so we can see your new bird?