No you cannot. I have a 84' that I am the original owner of and I never (thank god and knock on wood) had a flat that required me to mount the spare tire. I have that ancient can in the garage, but is toast for sure.
I should point out that if your really ever expect to use that tire that it is probably toast itself as it is a very old tire. You need to go to a good general tire store and get them to order a replacment unit (I plan to do this shortly as mine is so cracked it would never be safe) and then as suggested buy a good DC pump. this was one of the first hide-a-spare implementations on a Japanese car and it gave our old 300's a pretty darn good amount of room in the back to move crap, groceries etc. I used my old 84' many times for big moves and it held a truely amazing amount of stuff
