More information is needed to properly answer your question. Are you talking about your particular model, version , and barrel length? The model number ending with "-6" means yours was the 6th version. There were also variations of that model with those same numbers listed by name too. Is there a name associated with your gun? The names may or may not be printed on the gun. They may be listed on the box though. There is no 7" barrel made as a standard barrel size, unless of course it was a custom made special order. Standard barrel sizes could be 6.5" or 8 3/8". You need to measure from the muzzle to the front of the cylinder for an exact size. I assume you have a 6.5" barrel. Correct? Did you buy the gun new? You show rubber grips on your picture, were they original with the gun from the factory? Were there any other accessories that came with the gun?
Answering these questions should give us enough information to find an answer for you.