11-48 .410 with factory vented rib

[t_ray850]

I inherited a Remington 11-48 .410 with a factory vented rib. It is a full choke and uses 3" or shorter shells. The date code on the left side of the barrel is WA which makes it manufactured in August of 1954. The serial number on the receiver and the barrel do match. Next to the date code is a proof make that looks like an upside down hatchet and under this is what looks like a bell. On the right side is the (REP) and than a star. Can anyone tell me what the proof mark next to the date code means and what the star next to the (REP) means? Also how do I know what grade this gun is? It is in 99% condition, has very nice walnut checkered stocks but no engraving on the receiver. The serial number is 41139XX. I do not want to sell it as it belonged to my grandfather, but I would like to learn more about the gun. Sorry if I didn't explain the proof marks right. Any help would be greatly appreciated.