If the price is right, grab that bike quick. It's a Gran Sport LTD. I owned the identical bike brand new in 1978 and put over 20K miles on it before I stopped riding it in 1981. I now own two of them.
The only real issue with Garellis in general, is the rubber clutch. It has a tendency to swell up and stick. Other than that, they are pretty bulletproof. If you get it, you may have to open up the tranny cover and replace the 6 rubber clutch "bushings". They had a tendency to melt and stick to everything inside the tranny.
That oil injection was stock equipment and "state of the art" back in 1978. It was a huge convenience over pre-mixing. However, over time, they got very difficult to pump. I still have mine on both my GS LTD's just to keep the bike oiginal.
If you decide not to get it, let me know so I can take a crack at it :-) (edited)