SeaNymph built the same semi vee 14ftrs for years, decades maybe, w very few, if any, changes.
Your best bet would be to contact Lowe (current owner) and ask them. And thats a stretch. The vast majority of boat builders dont keep detailed records for long. Alumacraft is the only one I'm aware of that can use 1950s serial#s to decode year of manufacture.
Although it may have been used as a HIN, the 480176 is a serial number not a HIN.
If it doesnt have a conforming 12digit HIN on the starboard rear side of the transom, it was built prior to 1972, before HIN were required.
Good luck and post a pix when you can