John,
You do not say if your car is a Coupe or a Convertible.
Stock '69 Coupes were equipped with either a 4 or a 5 leaf spring.
Stock '69 Convertibles can with a 5 leaf spring.
If there are only 3 leafs in your present spring, something has
been changed. The 3 leaf spring was the aftermarket replacement spring
for the mono leaf.
The mono leaf and it's 3 leaf replacement do not have a centerbolt
head on the top side of the spring. While the 4 and 5 leaf springs do.
The centerbolt head locates the spring to the axle. The mono leaf and
it's 3 leaf replacement are located to the axle by the axle pads which
surround the spring.
Because of this locating method, the mono and 4 or 5 leaf multi
leaf springs are not interchangeable without our Conversion Kit Part
Number MP245K.
It is possible that the axle has been changed on the car or there
are more leaves than you 1st saw. To be sure of getting the right spring
it would be a good idea to remove one of your springs and double check
the number of leaves and to see if the centerbolt head is there or not.
In any case we have the spring you need including the mono leaf.
Mike