The sticker in the photo is the one you need. Your stuff is legal, it's just a bit out of date. One of our club's best pilots still uses an AM system in one of his planes. He bought it new many years ago and it still works, so there's no reason to change.

Still, I'd probably try to sell all of the AM transmitters and receivers and buy a current model Skysport 4 ($120 new) or 4EXA ($140 new). That way you know you have something compatible with modern trainer boxes and transmitters.

If you stick with the AM system, definitely keep the one with trainer cord provision. The next potential snag is finding a trainer box that will work with it. I get the impression that the trainer box has to be another old AM radio and that one based off of an FM transmitter will not work.

Futaba has two trainer cords for the older radios with round connectors.
http://www.futaba-rc.com/radioaccys/futm4400.html
Stock Numbers:
FUTM4400 MTCAM 6' Trainer Cord AM-Gray
FUTM4410 MTCFM 6' Trainer Cord FM-Black

Trainer cord info page
http://www.futaba-rc.com/radios/trainer-cord.html