Looks like a Mark VI from around 1968. Nice vintage, but yours appears to have seen some use (an old school horn, perhaps?), and needs substantial work, based on the dings and missing keyguards. I would also suspect it to be relacquered.
Value? Um... I'm guessing (it's not obvious from the photos you posted) that this is a low-Bb model. I'd assume it needs a total overhaul and some body straightening, in addition to replacement of the missing parts. The crook looks like it's taken a hit, and that can really affect the way a horn plays. So...I don't think I'd pay more than $2200-$2800 in its current condition. That may sound like a low-ball offer, but I have one of a nearby vintage, and I know firsthand how problematic some of these issues really can be.
Hope this helps--good luck.
Value? Um... I'm guessing (it's not obvious from the photos you posted) that this is a low-Bb model. I'd assume it needs a total overhaul and some body straightening, in addition to replacement of the missing parts. The crook looks like it's taken a hit, and that can really affect the way a horn plays. So...I don't think I'd pay more than $2200-$2800 in its current condition. That may sound like a low-ball offer, but I have one of a nearby vintage, and I know firsthand how problematic some of these issues really can be.
Hope this helps--good luck.