No, those springs are pretty stout. it would take a lot of backpressure to cause the joint to leak. Another advantage to that style header is that the runner lengths can be tuned if the header is made to accept spacer pipes. If not, it's just for ease of installation/removal.
__________________
-Harry
AIM: NDcissive
CRX and Pre '92 Civic, Engine Tech and Tuning, & Track and Autocross Forum Mod