Kinda looks like a mix and match. If it's a Phantom, it was a red one, not a black one. The red ones had the black accents as shown. It generally looks like it has the right paint markings, but it's odd to me that the red would've become brownish. Someone might have swapped the crankset (should be a big 52T ring) and wheelset (should be chrome) out to gain the 3-speed hub, and maybe a bit lower gearing overall. The Phantom was not a light bike, and the gearing they came with would've made hills tough. If it is a Phantom, it's missing the head and tail lights in addition to the tank. Those can be pricy to replace; my red Phantom is in a similar state (but also housepaint blue). I would start by checking the serial number. That would at least let you pin down the year.
