IMHO the bike is in need of restoration. Assuming the frame is the color as seen in the pictures then you would need to at least have it repainted. In addition, there are items on the bike that need to be replaced such as the front fender/mudguard, seat etc. Even though the pipes are HM300, they are still early Honda fitment (maybe not on a Sandcast) but certainly Honda product so that would be one item I would keep. A set of HM 300s' may not be original to a sandcast but they are acceptable replacements like batteries and tyres, and are way better than a set of Yamiya No Nos. If you want pristine then have them rechromed or if that's not possible then opt for the Yamiya. Again this is my take
To recap, I would restore the bike to pristine order and enjoy the fruits of your labour. Be sure to check the tank and petcock for originality as this VIN should have the early 17litre tank and petcock. Also ensure the other items such as brake pedal, top triple clamp, rear foot pegs, horn, tacho (I think the speedo is a K1), switches, brake three way union, airbox, frame #8 bolts etc etc etc etc, are restored rather than replaced as these items are common only to these early VIN bikes KP