Are 340’s rare

rare, not really... can always find them for sale.. valuable.. for sure and will only go up in value. 340s have a mystical reputation which will never go away and guys will pay stupid money for one instead of a 360 for 1/8th the price. If you don't need to sell it, oil it up good and put it under a bench for 10 years and it will double in value... no joke. i don't get it myself though.