What a handsome pair!!! Not that many people are familiar with working line sables - I know the first time I saw a sable, I did not recognize it as a German Shepherd, so used was I to only seeing black and tans.
It seems that most of us, at one time or another, get asked if we would breed our dogs. But you are thinking along the right lines - doing it right is a huge responsibility. People asking you to breed may just be looking for a puppy on the cheap, and that is a pretty poor reason to breed a dog.
Just enjoy your dogs. If people ask you about breeding them, just answer "Thank you, but these dogs are not for breeding". If people like your dogs and want one like them, direct them to the breeder you got them from.
Good breeders didn't become good breeders because one day, they started thinking about breeding the dog they own. They were first and foremost dog people that were neck deep into everything about their breed - they had trained and titled numerous dogs, participated in a bazillion different dog activities and sports, had hands-on training of working dogs, read everything about their breed, studied pedigrees and lines, sought out and hung out with knowledgeable dog people and breeders to learn all they could, THEN after making dogs their life and obsession, went into breeding because of the knowledge they have accumulated over the years.
That would be one reason to breed. Your dogs may be super nice (as is mine!), but that does not mean they should be bred. If your gut is telling you "Well . . . I'm not sure about this", follow your gut feeling.