I owned a K6-2 450@500 since two weeks ago, and I believe yours is running a litle bit too hot.
With hot summer temperatures (sometimes over 35ºC and no air-conditioning but open case), standard heatsink, standard fan, and overclocked from 450 to 500 it went to a max of 53º. This is with a Vcore of 2,4 which is 0,2 volts over the specs.
Considering all of this, you may think of better cooling if you want it not to flirt with those max 65ºC of AMD's specs.
There are a couple of easy changes that make quite a good impact in temps. First of all, install CPUIddle. It dropped my temps around 11ºC when iddle and in benchmarks it did'nt make any difference between having it running or not.
Good ventilation of the case is crucial. I also saw an improvement by applying thermal grease. Since K62 wear a metallic plate, you can mess quite a lot with them and see no damage (unlike FC-PGA or Durons/Thund).
Last thing I did was to add to the normal fan a big one from an old AT power unit that costed me nothing. With all that my max temp in summer became 44º, and lately when iddle it was at the low thirties (32º).
Saludos a todos