I guess it would depend on how much leeway there is with regard to the various timings in the system. If the specs are quite tight (5% or less tolerance) then it could easily cause trouble in any number of places, if the specs are lenient (up to a 10% deviation) then it shouldn't be a problem.

The big unknown is how much deviation is already present in the system due to the sheer age of the components. It's basically impossible to know if the two add up together to exceed the tolerance built into the system.

It's probably one of those "you won't know until you try it" situations.