It looks to be in great shape but are older pressure cookers safe?
Yes but I'd look for a book about how to use it safely. It can be really handy for quick meals and canning.
And you definitely need to replace the gasket, if it has one. Most of the traditional manufacturers of these are still in business, so you shouldn't have any problem finding a gasket. If it has a gauge, you need to get it re-calibrated. Manufacturers sometimes do this, but so do some state agricultural or extension offices and some master food preservers.
I agree you should look for a manual which you should be able to find online. Another thing is if it comes with a pressure gauge you might want to get it checked to make sure it is calibrated properly.