Hi Christopher,

Thank you for contacting Mearto with your appraisal inquiry.
This looks to be circa 1940s - does that align with when your great grandfather would have purchased it (was he the original owner?)
Based on the photos and information provided, and subject to examination, this is:

A vintage Rickenbacker "Electro" lap steel guitar
circa 1940s
patent #2089171
With hardcase
(DIMENSIONS)
CONDITION: client represents this to be fully functional.
PROVENANCE: inherited
$800-1,200*
*represents a fair-market value for auction purposes; retail or asking price may vary.

Please let us know if you have additional items to appraise, and thank you again for using Mearto.