Best to do a compression check of all cylinders, but that is quite involved. I don't know why both the lift and injection pumps would be bad. If just the lift pump, you can bypass that and use an electric pump (~$35 ebay). You could try hooking one up as a test before you buy, but then if you get the engine running, he might jack up the price. I might offer low (~$500) for the risk the engine is bad. These cars are showing up in the junkyard regularly, so you won't have to pay >$700 for a good used engine like in the past.