Daryl,
Here's another .410 with the same style frame as your 410. It has serial number 356464 which I believe was made in 1946.
26 inch barrels choked Mod (#2) in the right barrel and Full (#4) in the left barrel. Weighs 5 pounds and 12 ounces, just about what Dr. Drew's pictured Lefever brochure says.
I bought the gun 54 years ago next month for $150.00. It has accounted for many, many cottontail rabbits and some grouse. In fact, on one grouse hunting expedition walking thru some tall cover, some stuff came drifting down from above. It was grouse poop and some of it got on the stock. That grouse got away. Probably with a big smile on its face!
And I shot the gun this past Thursday on the 5 stand.