Well Trisha, 
If what you say is indeed true...you have one of the holy grails of Oliver collectability.  And I would be glad to take it off your hands <!-- s:D --><img src="{SMILIES_PATH}/icon_biggrin.gif" alt=":D" title="Very Happy" /><!-- s:D --> haha
Anyway, in all seriousness, these tractors are pretty rare, but I was under the impression that the reason they were so rare is that they didnt have real production numbers for them since they didnt differentiate from the others serial number wise.  I dont know if they had airport 25 stamped on the tags or not.  I may be way off here.  Somebody who knows more jump in here and help this lady out