No, not really. It’s still in the constitution since the 1940s only because changing it would provoke a military reaction from China. Nobody actually believes it, not since CKS died in the 70s.

No-one in the government of Taiwan considers themselves the true government of China. But they’re stuck with the old constitutional claims from the 1940s still on the paper because any change to reflect reality would be called a “declaration of independence” by China, and trigger a military reaction.