100 % IT IS A BIG YES.
100% Yes?

HOW?
Will that lengthen my PR visa stamp when my passport is sent for PR visa stamping?
Well you have already submitted the Travel History...And that would have covered everything.
Delay because your passport is full of stamps??? NO....Reason is that they are not going to sit and go through your passport to see where you have been etc...and then do security checks. That is already been done before they send you Final Passport Request.
You should get your passport back in 1-2 months.