I am sorry to see that you did not receive a prompt answer to your question last evening.
I suspect that there weren't many veterinarians online at the time you placed your question.
The other difficulty is that it is hard to tell whether a pup with breathing difficulties needs emergency care without examining him.
But for future reference I can give you some guidelines.
If his gum and tongue color are a nice bubblegum pink color he is likely stable and can wait to see his veterinarian in the morning. Blue, gray or white gums indicate a need for emergency care.
If he is able to lat down and sleep comfortably, even if his breathing seems quite loud, he is likely stable and can wait to see his regular veterinarian in the morning. Dogs that cannot lay down and sleep and end up falling asleep standing or pacing until exhaustion, only to wake after a few minutes, need emergency care.
Loud breathing is distressing for owners, and certainly indicates difficulty exchanging air necessitating an examination and some diagnostic testing, but if the pup is relatively comfortable it doesn't always need an emergency visit.
Again my apologies for the lack of response by my colleagues last night.