My Grandfather was given a winchester 1200 from a family member that passed. When he got the gun it was given to him in parts that came to him in a bag.He had no idea what to do with it so it was passed to me. After putting the gun back together I test fired it, and when I racked the pump to eject the spent shockgun shell, the shell failed to eject and just fell in the chamber making impossible to feed another round. I took the gun apart again and inspected it and saw i was missing the ejector pin. I went online and found the part i need but in the description it says the part will need to be fitted? How hard is this to do? Should i just take it to a gunsmith?