Hmmmmm,Rarer...Yes and no....Assuming your mower is 100% accurate engine to base then,yes it is slightly rarer than a common correct series run model 4 0r 5...BUT only slightly:)Ok I guess as most know the Predicta is the rarest 110,000 128,000 approx.I use this number as this is where the model 3 and four intersect.Anyways some say rarer,but truthfully ive owned more model 4s than any other special maybee over 50 and this is not by choice it was what came up or on offer at the time.other than the predicta the next rarest in my opinon will be the unmarked department store models.Im not going to go into the 3 series of model 5 but the way id work it out is like this.from model 4(non predicta through the model 5s any number sequence from 128,000 to 300,000 aprox is what id call a true series special.there are so many variants of numbers after this they become confusing and un accountable.The series got lost from between here and the sheerline model 6.In summery I guess apart from the predicta and dept models.The lower the series no the rarer/more appealing it will be.But there are so many factors to consider.The main ones are,is it in good original shape/unrestored,are all parts there,has it been changed moded or tampered with,this is what makes a model RARE.This is my opinion only.Hope i havnt confused you:)
