Interesting one !
Under NEC4, I would say the Contractor the time bar principle definitely cannot be applied retrospectively as an extra bullet point has been added to clause 61.4, which basically means that if the PM instructs the C to proceed to a producing a quotation, the time bar has passed.
Under NEC3, there is not this provision, but equally there is no express provision saying that it can be applied retrospectively.
However, clause 61.3 effectively says that if the Contractor took more than 8 weeks from becoming aware to notify, then the Prices, Completion Date and any Key Dates are not changed. So it could be argued that, while the PM has instructed the quotation, the quotation should be for zero change.