Hi Paul,
Yes, there should be the usual free play on the clutch lever. If there is no slack, the thrust bearing will always be under load and will wear prematurely. Clutch thrusts are becoming hard to find - so take care of it!
Regarding the push rod:- The ends should be hardened, but you need to know what material it has been made from. The most likely materials are either mild steel or silver steel. Silver steel is easily hardened by heating and quenching - so try heating just one end to a cherry red and quench it in oil - if that end is too hard to file, it is silver steel and will then need tempering. Polish the hardened end, then gently heat it until it turns a straw colour - then quench again in oil. Repeat the process on the other end.
If the initial heating didn't result in any hardening, it is probably mild steel and will need to be case hardened. This involves heating the ends to a bright red and dipping in a carbon rich compound (Kasenit) and reheating before quenching in water. The depth of hardening can be increased by repeating the operation, but about 5 thou is the maximum you will achieve. With case hardening, there is no need to temper it.
Hope this helps,
Regards,
Eddie.