If it's in good condition, stop thinking and buy it. Most will go in the $450-$500 range, if not more. I own several very early "L" frames, and they are only non P&R Smiths I own. Good luck. You will not regret it.
assuming the gun functions well and aside rust or pitting what could be wrong cosmetically with a stainless gun that couldn't be polished away? if its go minor scratches is that a deal breaker?