Do rigs with dogs always smell?

[Narnia]

Hi everyone! I found a unit online, which I just found out that the unit has had a dog living in it for 2 years. We have been in rigs with very strong doggy odor, which made my lungs want to close up!

Do all rigs that have had dogs living in it have an odor? We are nearly 5 hours from the rig, so am asking here, to save ourselves a trip.

Thanks for your help in advance!