It is not possible to say if the car is all there or not from one shot like that. You need to take it apart to make sure or at least get a few pictures with the body off.
One thing apparently missing (not sure, again) is the mechanical speed controller which isn't worth much and even if you get one it's better you bin it. A basic electronic brushed speedo is cheap to buy new these days. The other electronics you need are transmitter, receiver and only one servo if you get the electronic speedo. The second servo would have been needed for the mechanical speedo. You might need a motor as well (should have a silvercan but it is not clear if it has one).
Bits for that vintage car (if you need any plastics) are easy to find as Tamiya has just released a couple of other cars that use the same chassis renamed DF01. There are more cars that use some of the bits, but that's your best bet. Mechanicals (gears, driveshafts, etc) are easy to get as well.
Good luck and check out the thread here (vintage TA02 fan or something like that). Alternatively there's the Tamiyaclub over in the UK, a website where you can find a lot of info, people with these cars and a forum as well as a trading section.
Team Greasy Weasel
The best upgrade to any car is some driver skill.