Normally you are invited to visit the pups or dogs OR they come to you. This would be a normal request as they want to meet the potential families and what you can offer the dog as well as to ensure that this is a good fit. They will ask alot of questions which is also normal.
Ask them if you should bring your dog as this would be very important for them to view the relationship between your dog and this new little one.
Best of luck and I hope it works out for you.