- Old design does not mean it's damaged and not work in these days.
It should work, don't worry. Some Chinese or other country still make such toy transceiver, under a couple of dollars.
- Yes, it needs an ordinary 8 ohms speaker. The same speaker works as microphone while you press the switch as Transmitting mode.
Since it's 27MHz RF circuit, solder each parts closely and make a couple of neat PCB.
Keep posting here how they work when you make it. I am also interested to such walkietalkies.