Age of two pianos

[pianotune05 at comcast.net]

Hi Everyone,
I need to find the age of two pianos, & the website "bluebook of pianos" doesn't list them. I do not own the Piano Atlas.  
One is a Wurlitzer serial number 7226
the other wurlitzer  92921200 
I"m not sure why the serial number is so long on the second one.  I need these for a possible buyer.  Thanks for help in advance. 
Marshall
Villa Park, IL