Well, first off, there's no such thing as a "red nosed pit bull" nor a "blue nosed pit bull" or any other nose color of a pit bull. There's not multiple breeds of pit bulls and the color of a pit bulls nose doesn't make it a different breed of pit bull. A dogs nose color is just a color - there's nothing special about a color of a dog's nose.
The only true "red nosed pit bull" is Old Family Red Nose (OFRN). OFRN dogs are red with red noses. Some dogmen do not appreciate the OFRN strain, one famous dogman said that he would cull any red dog that came onto his yard as he didn't see the use for them. I personally love the OFRN strain. OFRN APBTs make excellent working dogs and there's very few breeders out there that are still breeding this strain.
The "blue nosed pit bull" does not exist. In fact, there is no such thing as a blue nosed anything. Blue nose is not a bloodline, and there's definitely nothing special about a blue nosed dog. My personal opinion is that blue nosed dogs are curs. Blue nosed often refers to the American Bully, and sometimes the Am. Staff, NOT the American Pit Bull Terrier. The blue color is extremely common in American Bullies. There is no such thing as a blue nosed pit bull, and in my opinion, APBTs aren't blue/do not come in blue.
Let's take a look at some examples of what people think are "red nosed pit bulls":
(these are just examples of dog's that I have "seen" that look like these dogs that the people considered to be "red nosed pit bulls" and what some people consider them to look like)
Black/white dog with black nose
Black and white dog with black nose
Brindle and white dog with black nose
White dog with pinkish nose
Red and white dog with pinkish nose
Here are some prime examples of Old Family Red Nose Dogs:
Notice that all of the OFRN dogs above are red with red noses. Does this mean that every red dog with a red nose is OFRN bred or even an American Pit Bull Terrier? Absolutely NOT! Just because your dog is red and has a red nose can even mean that it is a mutt. If you don't have a pedigree or know the pedigree on your "red nose" dog, then your dog is a mutt. And, since OFRN dogs are not "common" and the good ones are with select few good breeders/owners, it is very rare that these show up in the general public. OFRN bred dogs are not dogs that are or should be owned by the general public.
Let's take a look at some "blue nosed" bullies (very common and NOT pit bulls):
Now, let's take a look at some blue American Stafforshire Terriers (Am.Staff for short):
The above blue dogs are American Bullies and American Staffordshire Terriers, not American Pit Bull Terriers and should not be referred to as "pit bulls". They should be referred to as American Bullies or American Staffordshire Terriers because that's what they are. So, stop calling your dog a "blue nose" or "red nose" and stop calling your bully or Am. Staff a "pit bull".
Here's an image I've always appreciated: