I thought the pirc had 2....nf6
so queen swap would go: 1.e4 d6, 2. d4 nf6, 3.e5 dxe5, 4. dxe5 QxQ, 5. KxQ
And now it's white who loses the ability to castle. I play the pirc and I'm pretty happy with an early queen swap as shown in this post but I wouldn't be comfortable with the variation presented in your post - just because I'd feel my king was too exposed stuck in the middle so early. My reckoning though is based on the "general principle" of it being better to castle rather than concrete experience with the variations. I know some players aren't to worried about losing the right to castle if the queens are off and the centres a bit blocked up.