I bought a champion singel shot 410 about 8 years agon for $129. It does not have a serial number on it. The gun is old but I don't know how old. No cracks in the wood.
Your .410 probably uses the short shells and is of the vintage of about 1908 give or take.
I have one marked "model 155" has no serial # and was purchased in 1964
1955
in 1949
$250-$350.
No sn data published.
No published sn data
It was made by Iver Johnson after their Champion Model for Montgomery Ward
The 410 should have a smaller frame than the 12 gauge. For $100-$150, you should be able to get a whole 410 Champion.
serial # 50998 is 1945 value 700-1400 dollars based on condition
Ruger has sn data on their web site